chemical kinetics-assignment.doc

8/14/2019 CHEMICAL KINETICS-ASSIGNMENT.doc

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Sri Chaitanya IIT- JEE Academy

CHEMISTRY ASSIGNMENT

[Chemical Kinetics]

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1. The rate of chemical reaction (ece!t "ero order#

1#decreases from moment to moment $# remains constant thro%&ho%t

'# de!ends %!on the order of reaction # none

$. )adioactie decay follo+s ,,,,,, order inetics

1# $# I '# II # III

'. The acid hydrolysis of ester is

1# I order reaction $# /imolec%lar reaction

'# 0se%do %nimolec%lar reaction # none

. The reaction C'C22C$345a2 C'C225a4C$32 is

1# /imolec%lar reaction $# II order reaction

'# III order reaction # none

3. The rate constant of a II order reaction has %nits

1# mole l-1sec-1 $# litre mole-1sec '# litre mole-1sec-1 # none of the a/oe

6. 7or a reaction of II order inetics its 1T 2 is

1# a $# a1 '# a$ # a-1

8. The reaction $5a4Cl$9 $5aCl is fo%nd to follo+ III order inetics. Its molec%larity is

1# 1 $# $ '# ' #

:. If ;a< is the initial conc. 2f a s%/stance +hich reacts accordin& to "ero order inetic and

K is rate constant= the time for the reaction to &o to com!letion is

1# a K $# 2 Ka '# K a # 2K a

>. In a reaction= the rate is K[A] [?]$@'the 2.). is

1# 1 $# $ '# 5 3 # "ero

1. hich one does not infl%ence the rate of reaction

1# nat%re of reactant $# conc. of reactant

'# tem!erat%re # molec%larity

11. 7or the reaction A4? !rod%cts= it is fo%nd that the order of A is $ and of ? is ' inthe rate e!ression +hen conc. of /oth is do%/led= the rate +ill increase /y

1# 1 $# 6 '# '$ # 16


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1$. 7or the reaction A ?= it is fo%nd that the rate of reaction increase /y : times +henthe conc. of A is do%/led. The reaction is of BB.. 2.).

1# 1 $# $ '# ' #

1'. An increase in rate of reaction for a rise in tem!erat%re is d%e to

1# increase in collision fre%ency $# shortenin& of mean free !ath

'# increase in the n%m/er of actiated molec%les # none

1. The rate at +hich a s%/stance reacts is !ro!ortional to its

1# e%ialent +ei&hts $# molec%lar +ei&hts

'# n%m/er of moles # n%m/er of moles !er litre

13. The rate constant of a reaction has same %nits as the rate of reaction. The rate is of

1# "ero order $# first order '# second order # none of these

16. Increase in the concentration of the reactants leads to the chan&e in

1# heat of reaction $# actiation ener&y

'# collision fre%ency # none of these

18. 7or a molec%lar collision to /e effectie= it sho%ld satisfy the follo+in& condition

1# it sho%ld inole the molec%les hain& a certain minim%m amo%nt of ener&y

$# it sho%ld inole only ionic com!o%nds

'# it sho%ld inole molec%les hain& a certain minim%m amo%nt of ener&y and a!ro!er orientation

# it sho%ld inole t+o or three molec%les


3/39

1:. An endothermic reaction A ? has an actiation ener&y as J mole of A. If ener&ychan&e of the reaction is y J= the actiation ener&y of the reerse reactions is

1# D $# D y '# 4y # y D

1>. The reactions of hi&h molec%larity are rare /eca%se

1# many /ody collisions hae a lo+ !ro/a/ility

$# many /ody collisions are not fao%red ener&etical

'# actiation ener&y of many /ody collision is ery hi&h

# actiation ener&y of many /ody collision is ery lo+

$. The actiation ener&y of eothermic reaction A ? is $ .cal. The heat of reaction

is 3 .cal. The actiation ener&y for the reaction ?A +ill /e

1# $ .cals $# ' .cals '# 8 .cals # 3 .cals

$1. Increase in concentration of the reactants res%lts in

1# decrease in rate of the reaction $# increase in rate of the reaction

'# /oth increase or decrease in rate de!endin& %!on the nat%re of the reactants

# none of the a/oe

$$. 7or a chemical reaction $4y" the rate of a!!earance of " is .3 mol -1!er min.The rate of disa!!earance of +ill /e

1# .3 mol -1!er ho%r $# .3 mol -1!er min

'# .1 mol -1min-1 # .$3 mol -1!er min

$'. The actiation ener&y of a reaction is "ero. The rate constant of the reaction

1# increases +ith increase of tem!erat%re $# decreases +ith increase of

tem!erat%re

'# decreases +ith decrease of tem!erat%re # is nearly inde!endent of tem!erat%re

$. 2rder of reaction is

1# al+ays e%al to its molec%larity $# al+ays a fraction

'# al+ays an inte&ral n%m/er # the s%m of the e!onents in rate la+

$3. The s!ecific rate of a first order reaction de!ends on

1# the concentration of the reactants $# the concentration of the !rod%cts

'# tem!erat%re # time

$6. The correct e!ression for Arrheni%s e%ation sho+in& the effect of tem!erat%re on

the rate constant is

1#a2 2 1

1 1 2

EK T - T

K 2.303R T T= $# a2

1 1 2

EK 1 1ln -

K R T T

=


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'# Ea RTK = Ae #a2 1 2

1 2 1

EK T Tlog =

K 2.303 T - T

$8. 7or the first order reaction half-life is 1s. The time re%ired for the initial

concentration to red%ce toth

1 8 of its al%e is

1# $: s $# $ s '# (1#'s # (1#$s

$:. The rate la+ for the reaction

)CI45a2(a# )245aCl is &ien /y= )ate 9 K[)Cl] the rate of the reaction +ill/e

1# do%/led on do%/lin& the concentration of sodi%m hydroide

$# haled on red%cin& the concentration of alyl halide to one half

'# decreased on increasin& the tem!erat%re of the reaction

# %naffected /y increasin& the tem!erat%re of the reaction

$>. The rate constant of a reaction de!ends on

1# tem!erat%re $# mass '# +ei&ht # time

'. 7or a &ien rate la+ $A4? C4F= the actie mass of ? is e!t constant /%t that ofA is tri!led. The rate of reaction +ill

1# decrease /y ' times $# increase /y > times

'# increase /y ' times # %n!redicta/le

'1. Tain& the reaction A4$?!rod%cts to /e of second order +hich of the follo+in& isthe rate la+ e!ression for the reactionG

1#dx

= K[A][B]dt

$#2dx = K[A][B]

dt'#

2dx = K[A] [B]dt

#2dx = K[A]+[B]

dt

'$. Consider a &aseo%s reaction= the rate of +hich is &ien /y K[H][]. The ol%me of the

reaction essel containin& these &ases is s%ddenly red%ced to 1@th of the initial

ol%me. The rate of the reaction as com!ared +ith ori&inal rate is

1# 1@16 times $# 16 times '# 1@: times # : times

''. The rate of a reaction that does not inole &ases= does not de!end %!on

1# !ress%re $# tem!erat%re '# concentration # datalyst

'. 7or a reaction= a !lot of lo& (a D # ers%s time (t# is a strai&ht line +ith slo!e e%al to

K 2.303 = the reaction is of

1# "ero order $# first order '# second order # third order

'3. The rate constant of a reaction is 3.$1-1min%tes-1the order of the reaction is

1# one $# "ero '# t+o # three


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'6. The first order rate constant for decom!osition of 5$23is 6.>'1- sec-1. hat is half

chan&e time for decom!ositionG

1# 1$sec $# 1'sec '# 1sec # 1 sec

'8. The half-life !eriod of a first order reaction is 13 min%tes. The amo%nt of s%/stance

left after one ho%r +ill /e

1# one half $# one fo%rth '# one ei&ht # one siteenth

':. 7or a reaction A4$? C4F= the follo+in& data= +ere o/tained

E!t. initial conc. initial conc. initial rate of

(mol. -1# (mol -1# formation of F

[A] [?] (mol -1min-1#

1# .1 .1 6.1-'

$# .' .$ 8.$

1

-$

'# .' . $.::1-1

# . .1 $.1-$

The correct rate la+ e!ression +ill /e

1# )ate 9 K[A][?] $# )ate 9 K[A][?]$ '# )ate 9 K[A]$[?]$ # )ate 9 0[A]$[?]

'>. The rate of the reaction A4?4C!rod%cts is &ien /y 1 2 1 3 1 4- d[A]

r = = K[A] [B] []

dt

the order of reaction is

1# 1 $# $ '# 1 2 # 13 12

. In a reaction the rate +as fo%nd to /e inde!endent of the concentration of the

reactants. The reaction is of

1# 1storder $# $ndorder '# order 1.3 # "ero

1. hich one of the follo+in& factors does not infl%ence the reactions ratesG

1# concentrations $# tem!erat%re '# si"e of the essel # catalyst

$. In a m%ltiste! reaction= the oerall rate of reaction is

1# e%al to the rate of slo+est ste! $# e%al to the rate of fastest ste!

'# e%al to the aera&e rate of ario%s ste!s # e%al to the rate of the last ste!

'. hich of the follo+in& e!ression is correct for second order reactions (C refers to

initial concentration of reactant#

1# 1 2 0t ! $#-1

1 2t ! '#-2

1 2 0t ! #0

1 2 "t !

. The effect of tem!erat%re on reaction rate is &ien /y

1# Cla%si%s cla!eron e%ation $# Arrheni%s e%ation


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'# i//


7/39

The order of the oer all reaction is

1# $ $# 1 '#1

12

#

3. 7or a chemical reaction $H4M the rate of a!!earance of M is .3 mol -1 !ermin. The rate of disa!!earance of +ill /e

1# .3 mol -1!er ho%r $# .3 mol -1!er min.

'# .1 mol -1min-1 # .$3 mol -1!er min.

33. An endothermic reaction A ? has an actiation ener&y of 1 K.cals@mole and heat

of the reaction is 3 .cals@mole. The actiation ener&y of the reaction ?A is

1# $ .cal@mole $# 3 .cal@mole '# 1 .cal@mole # "ero

36. The decom!osition of a s%/stance ;)< taes !lace accordin& to first order inetics. Its

initial concentration is red%ced to 1@:thin $s. The rate constant of the reaction is

1# -11 24 ( $# -10.)* 1) ( '# -1ln 2 8 ( # -11 8 (

38. The half life !eriod of a first order reaction2.303 a

K = logt a - x

is

1# directly !ro!ortional to ;a< $# inersely !ro!ortional to ;a<

'# inde!endent of ;a< # !ro!ortional to (a D #

3:. The incorrect order indicated a&ainst the rate of reaction A4? C is

)ate 2rder )ate 2rder

1#d[]

= K[A]dt

1 $#d[]

= K[A][B]dt

$

'# 0d[A] = K[A][B]

dt$ #

d[A]= K[A]

dt1

3>. The minim%m ener&y necessary to !ermit a reaction to occ%r is

1# internal ener&y $# threshold ener&y

'# actiation ener&y # free ener&y

6. 7or a "ero order reaction

1# 1 2 0t ! $# 1 2 0T ! 1 '#2

1 2 0t ! #

2

1 2 0t ! 1

61. A first order reaction has s!ecific rate constant of $ min-1. The half-life of this reaction

+ill /e

1# 1.63' min $# .'8 min '# $ min # .3 min

6$. 7or a first order reaction +e hae 91 sec-1. The time for com!letion of 3N

reaction is

1# 1m sec $# m sec '# 8m sec # 1m sec


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6'. 7or the reaction A4$? C= the rate of reaction at a &ien instant can /ere!resented /y

1#d[A] 1 d[B] d[]

+dt 2 dt dt

= + = + $#d[A] 1 d[B] d[]

dt 2 dt dt= + =

'#d[A] 1 d[B] d[]

dt 2 dt dt = = + #

d[A] 1 d[B] d[]

dt 2 dt dt+ = + = +

6. In !hotochemical reactions

1# tem!erat%re has the same effect as on thermal reactions

$# tem!erat%re has o!!osite effect as on thermal reactions

'# tem!erat%re has no effect

# tem!erat%re may hae a little effect in certain cases

63. In the reaction A4?A? if the concentration of ;A< is do%/led= the rate of reaction+ill

1# /e do%/led $# /e decreased to one half

'# increase fo%r times # remain %naffected

66. The amo%nt of ( )12853 1 2 t - 25 ,nte% left after 3 min%tes +ill /e

1# 1 4 $# 1 2 '# 1 3 # none of these

68. The first order rate constant for the decom!osition of 5$23is 61-

second-1

. The halflife !eriod for the decom!osition in second is

1# 1133 $# 113.3 '# 11.33 # 1.133

6:. If the half-time for a !artic%lar reaction is fo%nd to /e constant and inde!endent of the

initial concentration of the reactions then reaction is

1# first order $# "ero order '# second order # none of these

6>. If initial concentration of reactants in certain reaction is do%/led= the half life !eriod of

the reaction do%/les= the order of a reaction is

1# "ero $# first '# second # third

8. The rate of reaction A4?!rod%cts is &ien /y the e%ation r9K[A][?]. If ? istaen in lar&e ecess= the order of the reaction +o%ld /e

1# $ $# 1 '# # %n!redicta/le

81. In the reaction= A4$? C4$F= the initial rate- d[A]

dt at t 9 +as fo%nd to /e

$.61-$m sec-1. hat is the al%e of- d[B]

dtat t 9 in m sec-1G

1# $.61-$ $# 3.$1-$ '# 1.1-1 # 6.31-'


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8$. The %nit of the elocity constant in case of "ero order reaction is

1# conc time-1 $# conc-1time '# conc-1time-1 # conc (time#$

8'. The conersion of molec%les A to ? follo+s second order inetics. Fo%/lin& the

concentration of A +ill increase the rate of formation of ? /y

1# a factor $ $# a factor of '# factor of 1 2 # a factor of 1 4

8. 2f the concentration of a reactant A is do%/led and the rate of its reaction increases /ya factor of $= the order of reaction +ith res!ect to A is

1# first $# "ero '# second # third

83. If initial concentration is tri!led= the time for half reaction is also tri!led= the order of

reaction is

1# "ero $# first '# second # third

86. )ate of chemical reaction can /e e!t constant

1# /y startin& the com!onents $# /y ee!in& the tem!erat%re

'# /oth of a/oe # none of a/oe

88. hich of the follo+in& into la+s has an oerall order of .3 for reaction inolin&

s%/stances and yG

1# ( )( )x /Rate = K $# ( ) ( )0.50.5

x /Rate = K

'#

( ) ( )

11.5

x /

Rate = K

#

( )( )

1.5

x /

Rate = K

8:. The hydrolysis of methyl formate in acid sol%tion has rate e!ression

[ ] +3rate = K "" the /alanced e%ation /ein& C22C'4$2

C224C'2. The rate la+ contains+ tho%&h the /alanced e%ation does not

contain+ /eca%se

1# more for conenience to e!ress the rate la+

$# 4ion is a catalyst

'# 4is an im!ortant constit%ent of any reaction

# All acids contain 4ions

8>. In a catalytic conersion of 5$ to 5'/y a/er


10/39

:1. 7or an eothermic reaction the ener&y of actiation of the reactant is

1# e%al to the ener&y of actiation of !rod%cts

$# less than the ener&y of actiation of !rod%cts

'# &reater than the ener&y of actiation of !rod%cts

# sometimes &reater and sometimes less than that of the !rod%cts

:$. In a reaction 4y!rod%cts= it +as fo%nd that (i# on do%/lin& the concentration of= the rate do%/led (ii# on do%/lin& the concentration on y= the rate of the reaction

increased fo%r times= the oer all order of the reactant is

1# ' $# $ '# 1 #

:'. The hydrolysis of ester in alaline medi%m is a

1# 1storder reaction +ith molec%larity 1 $# $ndorder reaction +ith molec%larity $

'# 1storder reaction +ith molec%larity $ # $ndorder reaction +ith molec%larity 1

:. 7or the chemical chan&e A ?= it is fo%nd that the rate of reaction do%/les +henthe concentration is increased fo%r times. The order A for this reaction is

1# t+o $# "ero '# one # half

:3. 7or reaction A4? $C4$F +hich of the follo+in& statements is not correctG

1# the rate of disa!!earance of ? is one fo%rth of the rate of disa!!earance of A

$# the rate of a!!earance of C is one half the rate of disa!!earance of ?

'# the rate of formation of F is one half the rate of cons%m!tion of A

# the rates of formation of C and F are e%al

:6. The %nits for the rate constant to first order reaction is

1# S-1 $# mol -1S-1 '# mol S-1 # mol-1S-1

:8. The rate of a certain reaction at different times are as follo+s

Time (min# 1 $ '

)ate $.:1-$ $.:1-$ $.:11-$ $.8>1-$

(moles litre-1min-1#

the order of the reaction is

1# one $# t+o '# three # "ero

::. The reaction= $A4$?!rod%cts= the follo+in& initial rates +ere o/tained at ario%sinitial concentrations

[A] [?] )ate (mol l-1sec-1#

.1 L .$ L .6


11/39

.$ L .$ L 1.:

.$ L .1 L .>$

The rate la+ for the reaction is

1# )ate 9 K[A]$[?] $# )ate 9 K[A][?] '# )ate 9 K[A]$[?] # )ate 9 K[A][?]$

:>. The reaction $$2$ $$242$is= [ ]2 2r = K "

1# "ero order reaction $# first order reaction

'# second order reaction # third order reaction

>. A s%/stance A decom!oses in sol%tion follo+in& the first order inetics. 7las I

contains 1 of 1 L sol%tion of A and flas II contains 1ml of .6 L sol%tion. After :

hr. the concentration of A in flas I /ecomes .$3L= +hat +ill /e time for concentration

of A in flas II to /ecome .'L

1# . hr. $# $. hr. '# . hr.

# %n !redicta/le as rate constant is not &ien

>1. The %nit of rate constant for a "ero order reaction is

1# litre sec-1 $# litre mole-1sec-1 '# mole litre-1sec-1 # mole sec-1

>$. The rate constant for a first-order reaction +hose half-life is : sec. is

1# 1.1-'sec-1 $# 1. sec-1 '# .8$1-'sec-1 # $.::1-'sec-1

>'. The rate of a chemical reaction do%/les for eery 1C rise in tem!erat%re. If the rate

is increased /y 6C= the rate of reaction increases /y a/o%t

1# $ times $# '$ times '# 6 times # 1$: times

>. hich of the follo+in& statement a/o%t the order of reaction is tr%eG

1# the order of a reaction increases +ith increase in tem!erat%re

$# the order of a reaction can /e determined from the /alanced e%ation

'# a second-order reaction is also /imolec%lar

# the order of a reaction can only /e determined

>3. The rate of the reaction 2 2 3 #g&+3 #g& 2 #g& +as meas%red as

[ ] 4 -1 -131 d

2 10 ,ol %e2 dt

+ = . The rates of the reaction e!ressed in terms of 5$and

$are rate in terms of 5$rate in terms of $.

( )-1 -1,ol %e ( )-1 -1,ol %e ( )-1 -1,ol %e ( )-1 -1,ol %e

1# 11- 11- $# '1- 11-

'# 11- 11- # $1- 61-

>6. The %nit for s!ecific reaction rate of second order reaction is


12/39

1# sec-1 $# mole litre-1sec-1

'# litre$mole-$sec-1 # litre mole-1sec-1

>8. The rate of a &aseo%s reaction is e%al to K[A][?]. The ol%me of the reaction essel

containin& these &ases is s%ddenly red%ced to one-fo%rth the initial ol%me. The rate

of the reaction +o%ld /e

1# 1 1) $# 1) 1 '# 1 8 # 8 1

>:. Fia"oni%m salt decom!oses as+ -

) 5 2 ) 5 2 l l+ . At C= the eol%tion of 5$

/ecomes t+o times faster +hen the initial concentration of the salt is do%/led.

Therefore it is

1# a first order reaction $# a second order reaction

'# inde!endent of the initial concentration of the salt # a "ero order

reaction

>>. hich one of the follo+in& rate la+s has an oerall order of .3 for the reaction

inolin& s%/stances H= = MG

1# ( )( )( )x / Rate = K $# ( ) ( ) ( )0.50.5 0.5

x / Rate = K

'# ( ) ( ) ( )11.5 0

x / Rate = K

# ( ) ( )

0

x Rate = K ( )

2

/

1. The conersion of A ? follo+s second order inetics. Fo%/lin& the concentrationof A +ill increase the rate of reaction /y a factor of

1# $ $# 1 2 '# # 1 4

11. In the reersi/le reaction1

2

K

2 2 4K

2" " the rate of disa!!earance of 52$is e%al to

1# [ ]21

2

2

2K "

K$# [ ] [ ]

2

1 2 2 2 42K " - 2K "

'# [ ]2

1 22K " # ( ) [ ]1 2 22K - K "

1$. The &ien reaction $7eCl'4SnCl$ $7eCl$4SnClis an eam!le of

1# first order reaction $# second order reaction '# third order reaction # none of

these

1'. 7or the reaction A4? C= it is fo%nd that do%/lin& the concentration of A increasethe rate times and do%/lin& the concentration of ? do%/les the reaction rate. hat

is the oerall order of the reaction

1# 3 2 $# '# 1 # '

1. A first order is half com!leted in 3 min%tes. o+ lon& does it need for >>.>N of the

reaction to /e com!letedG

1# $ ho%rs $# 1 ho%rs '#1

62

ho%rs # 3 ho%rs


13/39

13. In a reactionO A ?= the rate of reaction increases t+o times on increasin& theconcentration of the reactants fo%r times= then the order of the reaction is

1# $# $ '# 1 2 #

16. Lil t%rns so%r at C three times as faster at as C. ence E(actiation ener&y# of

t%rnin& of mil so%r is

1#2.303 2 313 263

log 3 al40

$#

2.303 2 313 263log #173& al40

'#2.303 2 40

log 3 al263 313

#2.303 2 40

log #173& al263 313

18. A &ra!h /et+een lo& ( )50T = and lo& (conc.# for nthorder reaction is a

strai&ht line. )eaction of this nat%re is com!leted 3N in 1

min%tes +hen conc. is $ mol -1. This is decom!osed 3N in t

min%tes at mol -1n and t are

1# .$ min $# 1= 1 min '# 1= $ min # = 3 min

1:. ra!h /et+een lo& and1

T ( is rate constant (s-1# and T the

tem!erat%re (K## is a strai&ht line +ith 2H93=-1 1 = Tan

2.303

.

ence Ea+ill /e

1# $.''$ cal $#2

al2.303

'# $ cal # none

1>. alf life ( )1T of the first order reaction and half life ( )2T of the second order reaction

are e%al. ence ratio of the rate at the start of the reaction

2

1T =

rate on%tant ntal on%tant

1# 1 $# $ '# .6>' # 1.

11. )ate constant of a reaction is .6>' min-1. Startin& +ith $ mol -1= rate of the

reaction after 1 min. +ill /e

1# .6>' mol -1min-1 $# 1.':6 mol -1min-1

'# .6>' mol -1min-1 # 6.>' mol -1min-1

111. The rate of a chemical reaction &enerally increases ra!idly een for small tem!erat%re

increase /eca%se of a ra!id increase in the

1# collision fre%ency

$# fraction of molec%les +ith ener&ies in ecess of the actiation ener&y

'# actiation ener&y


14/39

# aera&e inetic ener&y of molec%les

11$. 7or a reaction rate constant is e%al to rate of the reaction of all concentrations= the

order is

1# $# $ '# ' # 1

11'. )ate constant of a reaction is '.1-s-1= ener&y of actiation Ea9 1. J mol-1and

Arrheni%s constant A is 6.11s-1at $>: K. The al%e of rate constant as a Tis

1# $.11:s-1 $# 6.11s-1 '# infinite # '.61's-1

11. A tan&ent dra+n on the c%re o/tained /y !lottin& concentration of !rod%ct (mole -1#

of a first order reaction s. time (min# at the !oint corres!ondin& to time $ min%te

maes an an&le to ' +ith concentration ais. ence the rate of formations of

!rod%ct after $ min%tes +ill /e

1# .3: mole -1min-1 $# 1.8$' mole -1min-1

'# .$> mole -1min-1 # .:66 mole -1min-1

113. 7or reaction 'A!rod%cts= it is fo%nd that the rate of reaction increases -fold+hen concentration of A is increased 16 times ee!in& the tem!erat%re constant. The

order of reaction isG

1# $ $# 1 '# ' # .3

116. The reactionP $2' '2$= is assi&ned the follo+in& mechanism

I. 2' 2$42

II. 2'42 2%lo' 2"

The rate la+ of if the reaction +ill therefore /e

1# [ ] [ ]2

3 2r ! " " $# [ ] [ ]

2 1

3 2r ! " "

'# [ ]3r ! " # [ ] [ ]

2

3 2r ! " "

118. Fecom!osition of 5$23occ%rs in the follo+in& manner $5$23 52$42$its rate ise!ressed in three +ays

(i#[ ]

( )2 5 11 2 5d "

9 "dt

= (ii#( )

( )2 1 2 5d "

9 "dt

= (iii#( )

( )2 11 2 5d "

9 "dt

=

hat is the relation /et+een Q :9

1# 9 :9 $# 9 $ :9 '# :9 9 $ # :9 9 1 3

11:. All chemical reactions tae !lace at a definite rate de!endin& on the conditions= of

+hich the im!ortant are

1# concentration of reactants $# tem!erat%re


15/39

'# radiation # !resence of a catalyst

11>. The rate constant of a reaction de!ends on

1# tem!erat%re $# mass '# density # time

1$. The rate at +hich a s%/stance reacts de!ends on its

1# atomic mass $# e%ialent mass '# molec%lar mass # actie mass

1$1. The rate e!ression for a reaction is 3 2 -1rate = 9[A] [B] = the order of reaction is

1# $# 1 2 '# 3 2 # 5 2

1$$. hich of the follo+in& rate la+ has an oerall order of .3 for the reactions inolin&

s%/stances = y= "G

1# ( )( )( )x / Rate = 9 $# ( ) ( ) ( )0.50.5 0.5

x / Rate = 9

'# ( ) ( ) ( )11.5 0x / Rate = 9 # ( ) ( )( )

0

x

2

/

R Rate =

1$'. The reaction A($?( C(F( is an elementary !rocess. In an e!erimentthe initial !artial !ress%re of A Q ? are 0A9 .6 and 0?9 .: atm. hen 0C9 .$

atm the rate of reaction relatie to the initial rate is

1# 1 48 $# 1 24 '# * 1) # 1 )

1$. If concentration are meas%red in mole@lit and time in min%tes= the %nit for the rate

constant of a 'rdorder reaction are

1# mol lit-1min-1 $# lit$mol-$min-1 '# lit. mol-1min-1 # min-1

1$3. A radioactie element has a half life !eriod of 1 days. o+ m%ch of it +ill remain

after 11$ days

1#1

32$#

1

25)'#

1

512#

1

128

1$6. 7or a first order reaction the !lot of lo& t

[A] Rs t is linear +ith a

1# !ositie slo!e and "ero interce!t $# !ositie slo!e and non "ero interce!t

'# ne&atie slo!e and "ero interce!t # ne&atie slo!e and non "ero interce!t

1$8. The rate la+ for the reaction

)Cl45a2(a# )245aCl

is &ien /y )ate 9 [)Cl]. The rate of the reaction +ill /e

1# %naffected /y increasin& tem!erat%re of the reaction

$# do%/led on do%/lin& the concentration of 5a2

'# haled on red%cin& the concentration of 5a2 to one half


16/39

# haled on red%cin& the concentration of )Cl to one half

1$:. 7or a &ien reaction of first order= it taes $ min%tes for the concentration to dro!

from 1. mol litre-1to .6 mol litre-1. The time re%ired for the concentration to dro!

from .6 mol litre-1to .'6 mol litre-1+ill /e

1# more than $ min%tes $# less than $ min%tes

'# e%al to $ min%tes # infinity

1$>. The %nit of rate constant of a reaction hain& order 1.3 +o%ld /e

1# ( ) 17 2

-1 -1,ol %

$# ( ) 37 2

-1 -1,ol %

'# (conc#- .3time-1 # (conc#- .83time-1

1'. A catalyst lo+ers the actiation ener&y of the for+ard reaction /y $ J mol -1. It also

chan&es the actiation ener&y of the /ac+ard reaction /y an amo%nt

1# e%al to that of for+ard reaction

$# e%al to t+ice that of the for+ard reaction

'# +hich is determined only /y the aera&e ener&y of !rod%cts

# +hich is determined /y the aera&e ener&y of !rod%cts relatie to that of reactants

1'1. The half-life !eriod of a radioactie element is 1 days. After 36 days= one &ram of

the element +ill red%ce to

1# ( )1 2 g $# ( )1 4 g '# ( )1 8 g # ( )1 1) g

1'$. 7or a second order reaction of the ty!e rate 9 [A]$= the !lot of 1@ [A] ters%s t is linear

+ith a

1# !ositie slo!e and "ero interce!t $# !ositie slo!e and non "ero interce!t

'# ne&atie slo!e and "ero interce!t # ne&atie slo!e and non "ero interce!t

1''. The follo+in& statement(s# is (are# correct

1# A !lot of lo& K ers%s 1@T is linear

$# A !lot of lo& (# ers%s time is linear for a first order reaction H0

'# A !lot of lo& 0 ers%s 1@T is linear at constant ol%me

# A !lot of 0 ers%s 1@R is linear at constant tem!erat%re

1'. The decom!osition of Cl$28at in the &as !hase to Cl$ and 2$ is a first order

reaction

(i# After 33 seconds at K the !ress%re of Cl$28 falls from .6$ to . atm. The

rate constant and !ress%re of Cl$28after 1 sec of decom!osition at this tem!erat%re

are

1# 3.$1-sec-1P .3 atm $# 6.$1-'sec-1P .'' atm

'# 3.:1-'sec-1P . atm # .61-'sec-1P .3 atm


17/39

1'3. S%!!ose one does not hae an e!erimental !roced%re to follo+ the inetics of a first

order reaction +ith a half life less than .' nano seconds= then

1# The minim%m al%e of rate constant that can still /e meas%red is $.'111$sec-1

$# The maim%m al%e of rate constant that can still /e meas%red is :.'1611$hr-1

'# The minim%m al%e of rate constant that can still /e meas%red is more than

:.'1611$hr-1

# The maim%m al%e of rate constant= that can still /e meas%red is less than 31-1

hr-1.

1'6. 83N of a 1st order reaction +as com!leted in '$ min%tes. hen +as 3N of the

reaction com!leted

1# $ min $# min '# 16 min # : min

3# none of these

1'8. 7or a &eneral reaction=

aA4/? cC4dF

the rate of reaction may /e &ie as

1#;A

A B

d 1r = - 9

dt a = $# a ;B A B

d 1r = - 9

dt ; =

'#a ;A B

d 1r = 9

dt = # a ; A B

d 1r = - 9

dt d =

1':. The half life of a second order reaction is

1# 172t = 0.)*379 $# 172 0t = 9[A] '# 172 0t = [A] 7 9 # 1720

1t =

9[A]

1'>. Accordin& to Arrheni%s the relationshi! /et+een rate constant= and tem!erat%re can

/e &ien /y

1# - Ea RT9 = Ae $#a2 2 1

1 1 2

E9 T - Tlog =

9 2.303R T T

'# aE

log9 = logA -2.303RT

# 9 - $.'' )T lo& K

1. hat +ill /e the amo%nt of ( )n, 172< t 25 ,n= left after 3 min%tesG

1# 1@$ $# 1@ '# 1@' # 1@1

11. hat is the actiation ener&y for the decom!osition of 5$23as 2 5 2 21

" 2" "

2

+

If the al%es of the rate constants are '.31-3 and 6.>1-' at $8C and 68C

res!ectiely

1# 1$1$J $# ::.3 J '# 11$ J # 11$.3 J


18/39

1$. 3N of the amo%nt of a radioactie s%/stance decom!oses in 3 years. The time

re%ired for the decom!osition of >>.>N of the s%/stance +ill /e

1# 1 years $# /et+een 1 and 3 years

'# less than 1 years # /et+een > and 3 years

1'. hich one of the follo+in& statements is +ron& re&ardin& molec%larity of the reactionG

1# It is calc%lated from the reaction mechanism

$# It may /e either a +hole n%m/er or fraction

'# It is the n%m/er of molec%les of the reactants tain& !art in a sin&le ste! chemical

reaction

# It de!ends on the rate determinin& ste! of the reaction

1. 1.':6 ho%rs are re%ired for the disa!!earance of 83N of a reactant of first-order

reaction. hat is the rate constant of the reactionG

1# '.61-'s-1 $# 8.$1-'s-1 '# $.81-s-1 #

1.:1-'s-1

13. 7or a first order reaction= the ratio of time for the com!letion of >>.>N and half of the

reaction is

1# : $# 1 '# > # 1$

16. A certain radioactie element A= has a half-life 9 t seconds. In (t@$# seconds the

fraction of the initial %antity of the element so far decayed is nearly

1# $3N $# $>N '# $1N # 18N

18. The terms rate of reaction and rate of a!!earance (or disa!!earance# of reactant (or

!rod%ct#

1# re!resent one and the same !hysical %antity

$# differ /y constant factor

'# are !ositie !arameters and hae same al%e

# may or may not hae same al%e de!endin& %!on the stoichiometric coefficient of

reactants (or !rod%cts# in the /alanced chemical e%ation

1:. 7or the first order reaction A( $?(C(= the initial !ress%re is 0A9 >mm &=the !ress%re after 1 min%tes is fo%nd to /e 1:mm &. The rate constant of the

reaction is

1# 1.131-'sec-1 $# $.'1-'sec-1 '# '.31-'sec-1 # 61-'sec-1

I. Following facts is taken to expess ate of t!e eaction in te"s of

stoic!io"etic coefficients.

Answe t!e #$estions at t!e en% of it.


19/39

Fo t!e eaction aA&'( cC&%)

dx 1 d[A] 1 d[B] 1 d[] 1 d[]= - -

dt a dt ; dt dt d dt= = + = +

1>. 7or the reaction in alaline a%eo%s sol%tion=

- -

33Br" Br" 2Br +

the al%e of rate constant at :C in the rate la+ for-Br"

t

+as fo%nd to /e .3

mol-1s-1. )ate constants +hen the rate la+ is +ritten for- -

3Br" Br

andt t

are

= interms of-

3Br"

t

in terms of-Br

t

1# .1: mol-1

s-1

.'6 mol-1

s-1

$# .1: mol-1s-1 .$8 mol-1s-1

'# .16$ mol-1s-1 .1: mol-1s-1

# .16$ mol-1s-1 .'6 mol-1s-1

13. )ate of formation of S2'in the follo+in& reaction

$S2$42$ $S2'

is 1& min-1. ence= rate of disa!!earance of 2$is

1# 3& min-1 $# 1& min-1 '# $& min-1 # $& min-1

131. A reaction follo+s the &ien concentration time &ra!h. The rate for this reaction at $

seconds +ill /e

1# 1-'L s-1

$# :1-'L s-1

'# $1-$L s-1

# 11-$L s-1

13$. In the follo+in& reactionO

xA /B

d[A] d[B]

log - log 0.3dt dt

= +

+here D e si&n indicates rate of disa!!earance of the reactant. Th%s= O y is

1# 1 O $ $# $ O 1 '# ' O 1 # ' O 1


20/39

13'. 7or a &aseo%s reaction= the rate is often e!ressed in terms ofd

dt

instead ofd

dt

ordn

dt

= +here C is the concentration and n is the n%m/er of mole. ence= relation

/et+een three e!ressions is

1#d 1 dn 1 d

dt > dt RT dt

= =

$#d dn d

dt dt dt

= =

'#d dn > d

dt dt RT dt

= =

# none of these

13. 7or the reaction $5' 5$4'$

[ ][ ]

[ ][ ]

[ ][ ]3 2 21 3 2 3 3 3

d d d 9 ? 9 ? 9

dt dt dt = = =

Then relation /et+een 1 2 39 ? 9 and 9 is

1# 1.3 19 9 ' 29 9 39 $# $19 $9 '' '# 19 $9 ' # 1 9 '$ 9

$'

II. Consi%e t!e following state"ent an% answe t!e #$estions at t!e en% of it.

T!e ate at w!ic! a s$'stance eacts is popotional to its acti*e "ass an%

t!e ate at w!ic! a eaction pocee%s is popotional to t!e po%$ct of acti*e

"asses of t!e eacting s$'stances.

133. This is called BBB.

136. 7or the com!le reactionP

( )++

3 3 2

Ag +2 Ag

[ ] ( )26 2 -2 -1 + 2 -1

3 3 2

dx2 10 ,ol % Ag - 1 10 % ag

dt

+ =

ence= ratio of rate constants of the for+ard and /ac+ard reaction isO

1# $18$mol-$ $# $1>$mol-$ '# 11-$$mol-$ # .31->-$mol$

138. In the reaction

2 2 3 +3 2

[ ] [ ] [ ]3 22 -3 -3 -1

2 2 3

dx=110 @ - 1 10 @

dt


21/39

[ ] [ ]

[ ]

3

2 2 5 2

2

3

dx10 @ $

dt

=

is

1# $# 113 '# 11-3 # 11-'

13:. In the follo+in& &ra!hical re!resentation for the reaction A ? there are t+o ty!esof re&ionsO

1# I and II /oth re!resent inetic re&ion at different time interal

$# I and II /oth re!resent e%ili/ri%m re&ion at different time interal I re!resents

inetic +hile II re!resents e%ili/ri%m re&ion

'# I re!resents inetic +hile II re!resents e%ili/ri%m re&ion

# I re!resents e%ili/ri%m +hile II re!resents inetic re&ion

13>. At a &ien tem!erat%re= 19 $for the reaction

A+B +

If 1 2dx

= 9 [A][B] - 9 [][]dt

In +hich set of the concentration reaction ceasesG

[A] [?] [C] [F]

1# .1 L .$ L .' L . L

$# . L .$3 L .$ L .3 L

'# .$ L .$ L .' L .$ L

# .$ L .$ L . L .$ L

III. Fo t!e eaction A+2B rodt

If ate law can 'e witten as x /dx = 9[A] [B]dt

t!en x is sai% to 'e o%e w..t. A an% + is sai% to 'e o%e w..t. (. If a

eaction in*ol*es "oe t!an one step, t!e o*eall eaction is o'taine% '+

a%%ing t!ese ele"enta+ steps. In s$c! cases, "olec$lait+ can-t 'e %eci%e%

'+ o*eall eaction on t!e 'asis of its stoic!io"etic an% ate e#$ation.

Howe*e, t!e o%e of an ele"enta+ step can 'e pe%icte% fo" its


22/39

"olec$lait+. In fact, t!e o%e of an ele"enta+ step is alwa+s e#$al to its

"olec$lait+. T!e slowest step is t!e o*eall ate %ete"ining step an% gi*es

o%e of t!e eaction.

T!e following eaction is fisto%e in A an% fisto%e in (

A&( /o%$ct, Rate 0 k1A21(2

16. )elatie rate of this reaction in essels I and II of e%al ol%me is

1# 1 O 1 $# 1 O $ '# $ O 1 # 1 O

161. The reaction of hydro&en and iodine monochloride is re!resented /y the e%ation

2 2 #g&+2l#g& 2l#g&+ #g&

This reaction is first-order in $( and also first-order in ICl(. hich of these

!ro!osed mechanism can /e consistent +ith the &ien information a/o%t this reactionG

Lechanism I O 2 2 #g&+2l#g& 2l#g&+ #g&

Lechanism II O 2%lo'

#g&+l#g& l#g&+#g&

1# I only $# II only '# /oth I and II # neither I nor II

16$. 7or the follo+in& reaction

( ) ( )3 2 33 3 l+ " "+l

( )3 3dx

=9 ldt

= hence= rate-determinin& ste! is

1# ( ) ( )3 33 3 l l + $# ( ) ( )3 2 33 3 l+ " "+l

'# ( ) ( ) +3 2 33 3 + " "+ # l l +

I3. Following popet+ is fo t!e gi*en o%e of a eaction. (ase% on t!is answe

t!e #$estions gi*en at t!e en% of it.

Ti"e of $n%egoing a %efinite faction of a eactant is in%epen%ent of t!e

concentation.

16'. 7or s%ch reactions (as a/oe#= concentration of the reactant after t+o aera&e life (also

called nat%ral life time# is red%ced to


23/39

1# .$3 $# 1 e '# 21 e # .83

16. hich re!resents a/oe-ty!e reaction o%t of I= II and IIIG

1# I= II and III $# I and III '# II and III # I and III

163. In the follo+in& reaction A 0rod%ct= I and II are t+o different sets of a/oe ty!ereactionO is e%al to

1# 1 min $# 3 min '# $.3 min # $ min

166. )ate constant of a reaction is .6>' min-1. If +e start +ith $ mol -1= it is red%ced to

$.3 mol -1in

1# 1 min $# $ min '# ' min # min

3. T!e ate constant fo t!e %eco"position of a cetain eaction is %esci'e% '+t!e e#$ation4

( )4

-1

10

1.25 10 K log 9 % =14 -

T

168. 0re-e!onential factor for this reaction is

1# 1 s-1 $# 11s-1 '# 1-1s-1 # 1.$31s-1

16:. Ener&y of actiation (in cal# is

1# 38.6 cal $# 1.$31cal '# 1. cal # 1 cal

16>. At +hat tem!erat%re= rate constant is e%al to !re-e!onential factorG

1#41.25 10 K

T =14

$# T 9 '# T 9 # ( )414-1.25 10 K

18. hat is effect on the rate of the reaction at 1$8C= if in !resence of catalyst= ener&y of

actiation is lo+er /y 1 J mol-1G

1# 3 times $# 1 times '# 8 times # $ times

181. A t+o-ste! mechanism has /een s%&&ested for the reaction of nitric oide and

/romineO


24/39

19

2 2"#g&+Br #g& "Br #g&

29

2"Br #g&+"#g& 2"Br#g&

2/sered rate la+ is= rate 9 [ ]2 29["] Br

ence= rate-determinin& ste! is

1# 2 2"#g&+Br #g& "Br #g& $# 2"Br #g&+"#g& 2"Br#g&

'# 22"#g&+Br #g& 2"Br#g& # none of these

18$. A reaction taes !lace /y the follo+in& mechanism

A4?CAC4?

AC4FA4CF

The !otential ener&y !rofile for this is sho+n /elo+

Transition states are sho+n /y

1# I= R $# II= IR '# II= III= IR # III only

3I. Consi%e t!e following eaction

+ 2+

2Cn+2 Cn +

Halflife peio% is in%epen%ent of concentation of 5n at constant pH. At

constant 5n concentation, !alflife is 67 "in$tes at pH08 an% !alflife is 677

"in$tes at pH09.

18'. ence rate la+ is

1# +9[Cn] $#2+9[Cn] '#

0 +9[Cn] #20 +9[Cn]

3II. Fo t!e eaction A+B

1A2 1(2d[A]

-dt

6. 6.7 M 6.7 M 7.8: M "in6

8. 8.7 M 6.7 M 7.:7 M "in6

9. 6.7 M 8.7 M 7.8: M "in6

18. ence= rate la+ is

1# [A] [?] $# [A] [?]1@$ '# [A] # [?]


25/39

3III. Following ae t!e *al$es of Eaan% H fo t!ee eactions caie% o$t at t!e

sa"e te"peat$e

I 4 Ea0 87 k; "ol6, H 0


26/39

:7.7 6.

.88

'# .$1- .1- .18

# none of the a/oe

1:1. )ate la+ of the a/oe e!eriment is

1# [A] [?] $# [A]$[?] '# [A] [?]$ # [A]$[?]

1:$. )ate constant of the a/oe e!eriment is ( )2 -2 -1

n @ ,n

1# 1.'1-1 $# $.61-$ '# $.61-1 # 1.'1-$

>II. St$%+ t!e two p!otoc!e"ical eactions an% answe t!e #$estions at t!e en%.


27/39

Fo t!e o*eall eaction 'etween A an% ( to +iel% C an% ), two "ec!anis"s

ae popose%4

I. 5 -1 -1

1A+B AB +? 9 : 1 10 @ % =

II. 4 -1

1A A E? 9 1 10 %

=

10 -1 -1

2E+B +? 9 1 10 @ % =

?species wit! ae s!otli*e%@

1:'. )ate la+ for mechanism I +hen concentration of each is .1 L= is

1# 11-8L s-1 $# 11-6L s-1 '# 11-3L s-1 # 11-L s-1

1:. )ate la+ for mechanism II +hen concentration of each 1 L is

1# 11-L s-1 $# 111L s-1 '# 11-6L s-1 # 11-1L s-1

1:3. At +hat concentration of ?= rates of t+o mechanism are e%al

1# 1 L $# 3 L '# 8 L # 1 L

>III. Rea% t!e following in%$stial "et!o%s of H8S=an% answe t!e following

#$estions at t!e en%.

/ofesso Molina of t!e Massac!$setts Instit$te of Tec!nolog+ won t!e 6:

No'el /iDe in C!e"ist+ fo !is wok on at"osp!eic c!e"ist+. ne

eaction t!at !e !as st$%ie% in %etail is t!e aci% ain eaction w!ic! po%$ces

H8S= in t!e at"osp!ee. He !as popose% two possi'le stoic!io"etic

eactions4

/oposal A 4 2 3 2 4 "#g&+(" #g& (" #g&

/oposal ( 4 2 3 2 4 22 "#g&+(" #g& (" #g&+ "#g&

1:6. sin& sim!le collision theory= +hat reaction orders +o%ld /e e!ected for !ro!osal ?G

0ro!osal ? is tho%&ht to !roceed /y the follo+in& t+o-ste! !rocess

1

- 1

9

3 2 3 29(" +2 " (" .2 " #$a%t&

29

3 2 2 4 2(" .2 " (" + " #%lo'&

( )3 2 2 1 - 1(" .2 " % a o,lex 'hh % %ta;led ;/ h/drogen ;ond% and 9 F F 9 or 9

1# [ ] [ ]2 39 " (" $# [ ] [ ]2

2 39 " (" '# [ ]39 (" # [ ]29 "

/ART A

1. S%crose decom!oses in acid sol%tion into &l%cose and fr%ctose accordin& to first order

reaction= +ith half life of '.'''h at $3C. hat fraction of a sam!le of s%crose remains

after > hrsG


28/39

[AnsO .13'>8]

$. The rate constant for the decom!osition of 5$23 in CCl is 6.$1- s-1 at 3C.

Calc%late the rate constant at 1C if the actiation ener&y is 1' J mole-1.

[AnsO .1>'3 sec-1]

'. Calc%late the actiation ener&y of a reaction +hich do%/les in rate +hen the

tem!erat%re is raised from 1:C to $:C

[AnsO 1$.1' cal@mole]

. The actiation ener&y of the reaction A4? 0rod%ct= is $.6 cal@mole-1at C.The !rod%cts are formed at the rate of .1''L min -1. hat +ill /e the rate of !rod%ct

formation at :CG

[AnsO 11.8> L min-1]

3. The tem!erat%re coefficient of the reaction rate is $.:. o+ many times +ill the

reaction rate increase +hen the tem!erat%re is raised from $ to 83CG

[AnsO $:8.8 times]

6. T+o reactions !roceed at $3C at the same rate= the tem!. coefficient of the rate of the

first reaction is $. and of the second= $.3. 7ind the ratio of rates of these reactions at

>3C.

[AnsO .83 times]

8. In hydro&enation reaction at $3C= it is o/sered that hydro&en &as !ress%re falls from

$ atm to 1.$ atm in 3 min. Calc%late the rate of reaction in molarity !er sec. ()

9 .:$ litre atm.#

[AnsO 1.>11-3mol sec-1]

:. Fecom!osition of dia"o/en"ene chloride +as follo+ed at constant tem!erat%re /y

meas%rin& the ol%me of nitro&en eoled at s%ita/le interals. 7ollo+in& readin&s

+ere o/sered.

Time $ 33 8

Rol. of 5$ 1 $3 '' 16$

Calc%late order of the reaction.

[AnsO 7irst]

>. 7or a &aseo%s reaction= $A4?$ $A?= the follo+in& rate data +as o/tained at'C.

)ate of disa!!earance of ?$ Conce. (mole@litre#

Lole litre-1time-1 [A] [?$]

1.:1-' .13 .13

1.:1-$ .> .13

3.1-' .13 .3


29/39

Calc%late the rate constant for the reaction and rate of formation of A? +hen A is

[.$] and [?$] is [.] mole litre-1at 'K

[AnsO .: litre mole-1min-1= 1.$:1-'mole litre-1min-1]

1. Arsine decom!oses on heatin& to &ie arsonic and hydro&en. The decom!osition +as

st%died at constant ol%me and at constant tem!erat%re. The !ress%re at different

times are as follo+s.

t (ho%rs# 3.3 6.3 :

0(atm# .>63 1.6 1.86 1.1

Calc%late the s!ecific reaction rate ass%min& the reaction to /e first order.

[Ans .'> ho%r-1]

11. 7rom the follo+in& data sho+ that the decom!osition of $2$in a%eo%s sol%tion is a

first order reaction. hat is the al%e of the rate constantG

Time in mts. 1 $ '

5 $3 $ 13.8 1$.3 >.>

here 5 is the n%m/er of ml of KLn2 re%ired to decom!ose a definite ol%me of

$2$sol%tion.

[AnsO $.'1-$min-1]

1$. The decom!osition of 5$23accordin& to the e%ation $5$23( 52$(*$(= is afirst order reaction. After ' min%tes from the start of the decom!osition in a closed

essel= the total !ress%re deelo!ed is fo%nd to /e $:.3mm of & and on com!lete

decom!osition the total !ress%re is 3:.3mm &. Calc%late the rate constant of the

reaction.

[AnsO 3.$3:1-'min-1]

1'. At $8C it +as o/sered= d%rin& a reaction of hydro&enation that the !ress%re of $&as

decreases from $atm to 1.1 atm in 83 min. Calc%late the rate of reaction

(molarity@sec#. ien ()9.:$@litre atom K-1mole-1#

[AnsO :.1$1-6molarity sec-1]

1. T+o reactions of same order hae e%al !re e!onential factors /%t their actiation

ener&ies differ /y $.> J mole-1. Calc%late the ratio /et+een rate constants of these

reaction at $8C. ()9:.'1 J K-1#

[AnsO $.1>:1]

13. 7or a first order &aseo%s reaction H 4M= the rate constant is &ien /y.

K9311'sec-1e(- 3@)T#

here ener&y of actiation is taen in %nit of cals. Fetermine the tem!erat%re at

+hich H +o%ld decom!ose at the rate of .3N !er second.

[AnsO 6>.$: K]


30/39

16. The ariation of rate constant +ith tem!erat%re is &ien /y the inte&rated form of

Arrhenio%s e%ations.

a10

- Elog K = + on%tant

2.303 RT

If for a certain reaction

10 a

31)3.0

log K = - + 11.8** allate ET

[AnsO 18.:1 cal@mole]

18. The rate of acid catalysed ester hydrolysis of ethyl acetate in hydrochloric acid sol%tion

o/eys.

)ate 9 -d[e%ter]

=K[e%ter] [l]dt

If K9.1 L-1 h-1at $3C= calc%late the !se%do first order rate constant for Cl9.1

molar. 2n this /asis calc%late T1@$9 Time for half chan&e.

[AnsO 1-'ho%r -1O 6>' ho%r]

1:. S%!!ose 3 /acteria are !laced in a flas containin& n%trients for the /acteria so that

they m%lti!ly. A st%dy at '3C &ae follo+in& res%lts.

Time (min%tes# 13 ' 3 6

5o. of /acteria 3 1 $ :

Sho+ that rate of !rod%ction of /acteria is first order.

o+ many /acteria +ill /e after ' ho%rsG

[AnsO $.13]

1>. The actiation ener&y of the reaction A4? 0rod%ct is $.6 cal@mole at C. The

!rod%cts are formed at the rate of .1''L !er min%te. hat +ill /e the rate of !rod%ctformation at :CG

[AnsO )$9 ::.'3.1''911.8> L min-1]

$. The decom!osition of hydro&en !eroide in an a%eo%s sol%tion is a first order

reaction. Co%rse of reaction is st%died /y titratin& the 1ml reaction mit%re after

ario%s time interals. 7rom the follo+in& data calc%late the rate constant of the

reaction.

Time (seconds# 6 1$

KLn2 $$.: 1'.: :.$

[AnsO K9:.61-sec-1]


31/39

$1. 7or the thermal decom!osition of $-nitro !ro!ane at 'C= the actiation ener&y is

'>.' cal and the al%e of the constant A(fre%ency constant# is 1.11111sec-1. hat

is the half life !eriod of the reaction at 'CG ()9$ cal#

[AnsO ::'.> sec]

$$. T+o reactions (I#A 0rod%cts (II# ? 0rod%cts follo+ first order inetics. Therate of the reaction (I# is do%/led +hen tem!erat%re is raised from 'K to '1 K. The

half life for this reaction at '1 K is ' min%tes. At the same tem!erat%re ?

decom!oses t+ice as fast as A. If the ener&y of actiation for the reaction (II# is half

that of reaction (I#= calc%late the rate constant of reaction (II# at 'K.

[AnsO .'$8 min-1]

$'. The &as has !hase decom!osition of dimethyl ether follo+s first order of inetics.

C'C2C' C4$4C2. The reaction is carried at constant ol%me container at3C and has a half life of 1.3 mins. Initially only diethyl ether is !resent at a

!ress%re of . atm. hat is the total !ress%re of the system after 1$ mins.

[AnsO .8:: atm]

$. A"omethane decom!oses accordin& to the e%ation ( )3 2 2 ) 22 + . The

reaction +as st%died in a $ml flas at 'C. The data o/tained +ere as follo+s.

T@min 13 ' : 83

0total@min '6.$ $. 6.3 3'.1 3>.'

Calc%late rate constant and half life

[AnsO K91.$61-$m-133 mts]

$3. The half time of first order decom!osition of nitramide is $.1 ho%r at 13C.

5$52$(a# 5$2($2(l#

If 6.$& of 5$52$is allo+ed to decom!ose= calc%late

(i# time taen for 5$52$to decom!ose >>N

(ii# ol%me of dry 5$2 !rod%ced at this !oint meas%red at S.T.0.

$6. A dro! of sol%tion (ol%me .3 ml# contains '.1-6mole 4 ions. If the rate of

disa!!earance of the 4ions is 1.18L@sec= ho+ lon& +o%ld it tae for the 4ions

in the dro! to disa!!ear.

[AnsO 6.1->sec]

$8. The rate la+ for decom!osition of &aseo%s

5$23O 5$23 $52$41

22$

Is o/sered to /e


32/39

[ ][ ]2 5 2 5

- d "K "

dt=

A reaction mechanism +hich has /een s%&&ested to /e constant +ith this

eK

2 5 2 3 " " +" (fast#

1K

2 3 2 2" " " +"+"+ (slo+#

52452' 2K

22" (fast#

Sho+ that mechanism is consistent +ith the o/sered rate la+

$:. Fimethyl ether &aseo%s !hase decom!osition is C'2C' C4$4C2 at 83 Khain& rate constant 6.8$1-' min-1. Calc%late the time in +hich initial !ress%re of

mm in closed container /ecomes 83mm.

[AnsO :3.6 min]

$>. 7or the reaction $524$ 5$24$2 the al%e of D d!@dt +as fo%nd to /e 1.3torr@sec for a !ress%re of '3> torr of 52 and .$3 torr@sec for a !ress%re of 13$ torr.

The !ress%re of $/ein& constant. 2n the other hand= +hen the !ress%re of 52 is e!t

constant. 2n the other hand= +hen the !ress%re of 52 is e!t constant. Dd!@dt +as

1.6 torr@sec for a hydro&en !ress%re of $:> torr and .8> torr sec -1for a !ress%re of

18 torr. Fetermine order of reaction.

[AnsO 2)9']

'. A hydro&enation reaction is carried o%t at 3K. If the same reaction is carried o%t in

the !resence of catalyst at the same rate. The tem!erat%re re%ired is K.

Calc%late the actiation ener&y of the reaction if the catalyst lo+ers the actiation

/arier /y $ J@mol.

[AnsO 1 J]

'1. A radioactie element A says to ? I am half of +hat yo% +ere +hen yo% are one fo%rth

of +hat I +as. Loreoer I +as 1.1 times than +hat yo% +ere.U If the half life of A is

: days. hat is the half life of ?G

[AnsO : days]

'$. The first order reaction O S%crose l%cose47r%ctose taes !lace at ': K in .35Cl. At time "ero the initial total rotation of the mit%re is '$.. After 1 min%tes the

total rotation is $:.:. If the rotation of s%crose !er mol is :3= that of a&l%cose is 8

and fr%ctose is D:6.. Calc%late the half life of the reaction

[AnsO 68.$ mints]

''. The rate constant for the for+ard reaction A 0rod%cts is &ien /y

( )4

-1 1.25 10log K %e =14.34 -T


33/39

and the rate constant for the reerse reaction is 1.$1-sec-1at 3C. Calc%late the

al%e of maim%m rate constant !ossi/le for the /ac+ard section.

ien O Enthal!y of the reaction 9 -8: J@mol

[AnsO 111$ sec-1]

'. The decom!osition of a com!o%nd 0= at tem!. T accordin& to the e%ation

$0( V()(S(l# is a first order reaction. After ' min from the start of thedecom!osition in a closed essel the total !ress%re deelo!ed is fo%nd to /e '18mm& and after a lon& !eriod of time the total !ress%re o/sered to /e 618mm &.

Calc%late the total !ress%re of the essel after 83 min. ien O Ra!o%r !ress%re of S(l#

at tem!. T9'$.3mm &

[AnsO '8>.8'mm &]

'3. The time re%ired for 1N com!letion of a first order reaction at '88C is 33.$min and

the fraction of molec%les at 3C hae s%fficient ener&y to react is 1.>$1-16.

Calc%late its rate constant at C. Ass%min& the ener&y of actiation to /e constant

+ith in this tem!erat%re ran&e.

[AnsO K68'9 8.31$1-'min-1]

'6. The hydrolysis of ethyl acetate C'C22C$34$2 C'C224C$32 in a%eo%s

sol%tion is first order +ith res!ect to ethyl acetate. !on aryin& the ! of the sol%tion

the first order rate constant aries as follo+O

! ' $ 1

- 4 -11K 10 % 1.1 11 11

hat is the order of the reaction +ith res!ect to 4and the al%e of the rate constantG

[AnsO 1.11-1lit@mol@sec]

'8. 7or a first order reaction A ? the de!endence of rate constant on tem!erat%re is

&ien /y 10log 9 = 23.02 38 10

T

= +here T is in Kelin.

A $N sol%tion of A /y mass decom!oses to the etent of $3N in $ min%tes at $>: K.

hat +o%ld /e the N dissociation of A in the same time at ' K= if +e start +ith its

'N sol%tion

[AnsO 1N dissociated]

':. The rate of first order reaction is .mol lit-1sec-1at 1mts and .' mol lit1sec-1at $

min%tes after initiation. 7ind half life of the reaction.

[AnsO $.:>1 min%tes]

'>. The a!o%r !ress%re of t+o misci/le li%ids A and ? are 'mm and 3mm of &

res!ectiely. In a flas 1 moles of A is mied +ith 1$ moles of ?. o+eer as soon as

sol%te is added A starts !olymeri"in& into a com!letely insol%/le solid. The

!olymerisation follo+s first order inetics. After 1 min%tes= .3$3 moles of sol%te is

dissoled +hich arrests the !olymerisation com!letely. The final !ress%re of the


34/39

sol%tion is mm of &. Estimate the rate constant of the !olymerisation reaction.

Ass%me ne&li&i/le ol%me chan&e on miin& and !olymerisation and ideal /ehaio%r of

final sol%tion.

[AnsO 1.31-min-1]

. Some 0'( is introd%ced in a flas at 6C contains an inert &as. 0'!roceeds to

decom!ose into 0( and $( and the reaction &oes to com!letion. The total

!ress%re is &ien /elo+ as a f%nction of time. 7ind the order of the reaction and

calc%late the rate constant.

Time (sec# 6 1$

0(mm $6$. $8$.> $83.31 $86.

[AnsO Ist order]

1. 7or t+o reactions (i# 0 0rod%ct and (ii# V 0rod%ct the order of reaction (i# isone +hile that of reaction (ii# is t+o. At '8 K the ener&y of actiation of reaction (i# is

33 J@mol /%t +heneer this reaction is carried o%t in !resence of catalyst at the sametem!erat%re= the ener&y of actiation is 3' J@mol. Loreoer for the reaction (ii# +hen

tem!erat%re is increased from $>:K to ':K= the rate of reaction increases as many

times as for reaction (i# in !resence of catalyst. Calc%late the rate constant of reaction

(ii# at '1: K. If the !re-e!onential factor constant for reaction (ii# is '.361>mol-1lit

sec-1.

[K98.'' mol-1lit sec-1]

$. The com!le ( ) 2

3 5" G

+ reacts +ith +ater accordin& to the e%ation

( ) ( ) ( )2+ 3+

-

3 2 3 25 5" G + " " " +G and )ate9K[Com!le]

a[4]/

The reaction is acid cataly"ed i.e.= [4] does not chan&e d%rin& the reaction

Th%s rate 9 K1[Com!le]a= +here K19K[4]/

Calc%late a and / from the follo+in& data (t9$3C#

Com!le [4] 172T #hr& 374T #hr&

.1 .1 1 $

.$ .$ .3 1

[AnsO a91= /91]

/ART (

1. In the Arrhenio%s e%ation for a certain reaction= the al%e of A and Ea (actiationener&y# are 11' sec-1and >:.6 J mole-1 res!ectiely. If the reaction is of first

order= at +hat tem!erat%re +ill its half life !eriod /e 1 min%tesG

[AnsO '11.'K]


35/39

$. Consider t+o reaction I and II. The fre%ency factor of I is 1 times of II. The

actiation ener&y of I is .6 K cal hi&her than that of II. Calc%late the relation in

/et+een rate constant of I and II reactions at $$8C.

[AnsO 1.6]

'. 7rom the follo+in& data for the decom!osition of 552$ in a%eo%s sol%tion= sho+

that the reaction is of the first order.

Time in mts. 1 13 $3

Rol. of 5$in cc 6.$3 >. 1'.63 '3.3

. 7rom the follo+in& data sho+ that the decom!osition of $2$in a%eo%s sol%tion is a

first order reaction. hat is the al%e of the rate constantG

Time in mts 1 $ '

5 $3 $ 13.8 1$.3 >.>

here 5 is n%m/er of ml of KLn2re%ired to decom!ose a definite ol. $2$sol%tion

3. Ethylene oide +as decom!osed in the closed essel and fo%nd to tae !lace as /elo+

ith the hel! of follo+in& data= find the elocity constant of the reaction and sho+ that

the reaction follo+ed first order

Time 3 > 1:

0ress%re 116.31 1$$.$6 1$:.8 11.'8

6. The decom!osition of Cl$28at K in the &as !hase to Cl$and 2$ is a first order

reaction

(i# After 33 seconds at K the !ress%re of Cl$28falls from .6$ to . atm

calc%late that rate constant.

[AnsO 6.$'61-'

sec-1

]

(ii# Calc%late the !ress%re of Cl$28 after 1 sec of decom!osition at this

tem!erat%re.

[AnsO .'' atm]

8. Thermal decom!osition of a com!o%nd is first order. If 3N of a sam!le of the

com!o%nd is decom!osed in 1$ min%tes= ho+ lon& +ill it tae for >N of the

com!o%nd to decom!oseG

[AnsO '>:.8: min]

:. 7or the reaction A4? C= the follo+in& data +ere o/tained. In the first e!eriment+hen the initial concentration of /oth A and ? is .1 L= the o/sered initial rate of

formation of C is 1.1-L !er min%te. In the second e!eriment +hen the initial


36/39

concentration of A and ? are .1L and .'L res!ectiely. The initial rate is >.1-

L !er min%te. In the third e!eriment +ith the initial concentration of /oth A and ? is

.' 5= the initial rate is $.81-'!er min%te.

(i# rite rate la+ e!ression for this reaction.

2dxAn%H =K[A][B]dt

(ii# Calc%late the al%e of s!ecific rate constant for this reaction.

[AnsO 11-1litre4$mole-1time-1

>. 7or the reaction A4$? $C=

The follo+in& data +ere o/tained

Initial concentration Initial reaction rate

(mole@litre# (mole litre-1min-1#

[A] [?]

(i# 1. 1. .13

(ii# $. 1. .'

(iii# '. 1. .3

(i# 1. $. .13

(# 1. '. .13

rite do+n the rate la+ e!ression for this reaction &iin& yo%r e!lanation.

1. )ate la+ for the follo+in& reaction.

Ester44 Acid4Alcohol= is0

+dx K[e%ter] dt

= .

hat +o%ld /e the effect on the rate if

(i# Concentration of ester is do%/ledG

(ii# Concentration of 4ion is do%/ledG

[AnsO (a# rate is do%/led (/# remain same]

11. 7or the reaction A ?4C= follo+in& data +ere o/tained

t in seconds > 1:

Concn. of A 3.>' 1>.8 8.6$

0roe reaction is first order.

1$. The reaction $A4?4C F4$E= is fo%nd to /e first order in A= second order in ? and"ero order in C.

(i# ie the rate la+ for the a/oe reaction in the form of a differential e%ation


37/39

2 0dxAn%H =K[A][B] []dt

(ii# hat is the effect on the rate of increasin& the concentration of A= ? and C t+o

timesG

[AnsO : times]

1'. A first order reaction is 3N com!lete in ' min%tes at $8C and in 1 min%tes at 8C.

Calc%late the reaction rate constant at $8C and the ener&y of actiation of the

reaction in J@mole.

[AnsO .$'1 min-1= '.:: J@mole]

1. A first order &as reaction has K91.31-6 !er second at $C. If the reaction is

allo+ed to r%n for 1 ho%rs= +hat !ercenta&e of initial concentration +o%ld hae

chan&ed in the !rod%ctG hat is half-life of this reactionG

[AnsO 1$:.' ho%rs= 3.$3N]

13. Fecom!osition of 5$23( into 52$( and 2$( is a first order reaction. If the initial

concentration of 5$23(= i.e.= ( )2 5 0 " is .' mole litre1= +hat +ill /e concentration

after ' min%tesG )ate constant of the reaction is 1.'31-sec-1.

[AnsO .$'3 mole@litre]

16. The al%e of rate constant for decom!osition of nitro&en !entoide

2 5 2 4 2

1 " " "

2

+

is '.61-3at $3C and .:81-'at 63C. Sho+ that ener&y

of actiation for the reaction is $.: cal@mole. ()91.>:8 cal@de&@mole#

[AnsO $.: cal@mole]

18. Startin& +ith 1 mole of a com!o%nd A= it is fo%nd that the reaction is '@thcom!leted in

one ho%r. Calc%late the rate constant if reaction follo+s first order inetics.

[AnsO .$'1 min-1]

1:. Startin& +ith one mole of a com!o%nd A= it is fo%nd that the reaction is '@ com!leted

in 1 ho%r. Calc%late the rate constant if the reaction is of

(a# I order (/# II order

[AnsO 7or I order-K91.':6 hr-1= 7or II order-K9' litre mole-1hr-1]

1>. A dro! of sol%tion (ol%me .3ml# contains '.1-6 mole 4 ions. If the rate of

disa!!earance of the 4ions is 1.18L@sec= ho+ lon& +o%ld it tae for the 4ions

in the dro! to disa!!ear.

[AnsO 6.1->sec]

$. 7or the reaction A 0rod%ct= it +as fo%nd that the order for the chan&e +ith res!ectto A is $

(i# o+ does rate ary if conc. of A is red%ced /y $@'G

(ii# o+ does rate ary if ol%me of container is red%ced /y $@'G


38/39

(iii# Calc%late rate +hen [A]9$ mole litre-1and 172t =1 hr.

[AnsO (i# 1@> times (ii# > times (iii# $ mole litre-1hr-1]

$1. A Ist order reaction is 3N com!lete in ' min%tes at $8C and in 1 min%tes at 8C.

Calc%late the

(a# )ate constant for reaction at $8C and 8C

(/# Ener&y of actiation for the reaction

[AnsO '.:3 J@ml]

$$. The rate constant for the first order decom!osition of a certain reaction is &ien /y the

e%ation n K(sec-1#91.' -41.25 10

T

Calc%late O

(a# the ener&y of actiation (/# the rate constant at 3 K

(c# At +hat tem!erat%re +ill its half life !eriod /e $36 min%tesG

[AnsO $.:' Kl cal@ml 31' K]

$'. The &as has !hase decom!osition of dimethyl ether follo+s first order of inetics.

Cl'C2C' C4$4C2. The reaction is carried at constant ol%me container at3C and has a half life of 1.3 mins. Initially only diethyl ether is !resent at a

!ress%re of . atm. hat is the total !ress%re of the system after 1$ mins.

[AnsO .8:: atoms]

$. At ':C= the half life !eriod for the first order of decom!osition of $2$is '6 mts.

The ener&y of actiation of the reaction is $ J@mole. Calc%late the time re%ired for

83N decom!osition at 3C.

[AnsO $.'6 mts.]

$3. 7or the reaction $52Cl $524Cl$the rate constant is $.:1-3mol-1dm's-1at 'Kand 81-1 mol-1 dm' s-1 at K. Calc%late the ener&y of actiation (/# the

!ree!onential factor (c# rate constant at '3

K.

[AnsO 11 J@mol 1.>111'mol-1dm's-1161-']

$6. At a certain tem!erat%re= the half life !eriods for the catalytic decom!osition of

ammonia +ere fo%nd to /e as /elo+.

0ress%re in mm & 3 1 $

alf life in hrs. '.'$ 1.>$ 1.

7ind order of reaction

$8. The rate constant of a second order reaction is 3.81-3 dm' mol-1 s-1 at $3C and

1.61- dm' mol-1 s-1 at C. Calc%late actiation ener&y and Arrheni%s

fre%ency factor.


39/39

[AnsO 1'.$ cal@mol]

$:. S%/stance A reacts accordin& to a first order rate la+ +ith K931-3 sec-1. (a# If the

initial concentration of A is 1 L. hat is the initial rate and rate after 1 ho%r.

$>. In the inersion of s%&ar in the !resence of an acid follo+in& readin&s are o/tained

Time in mts. ' > $'

)otation in de&ree 46.83 41 4'.83 41$.83-1:.83

Calc%late rate constant

chemical kinetics-assignment.doc

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