Roll No.jksy ua-

Series DPS Code No. 34/1dksM ua- 34@1

Please check that this question paper contains 04 printed pages.

Code number given on the right hand side of the question paper should be written on the title page of the answer-book by the candidate.

Please check that this question paper contains 30 questions.

Please write down the serial number of the question before attempting it.

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CHEMISTRY (Theory)

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General Instructions: -

(i.) All questions are compulsory.(ii.) Marks for each question are indicated against it.(iii.) Questions number 1 to 8 are very short-answer questions, carrying 1 mark each. Answer these

in one word or about one sentence each.(iv.) Questions number 9 to 18 are short-answer questions, carrying 2 marks each. Answer these in

about 30 words each.(v.) Questions number 19 to 27 are short-answer questions of 3 marks each. Answer these in about

40 words each.(vi.) Questions number 28 to 30 are long-answer questions of 5 marks each. Answer these in about

70 words each.(vii.) Use Log Tables, if necessary. Use of calculators is not permitted.

34/1 P.T.O.( 1 )

1. Define activation energy of a reaction. [ 1 ]2. Give an example of ‘Shape-Selective Catalyst’ ? [ 1 ]3. Differentiate between roasting and calcination. [ 1 ]4. What is meant by ‘lanthanoid contraction’ ? [ 1 ]5. Write the IUPAC name of the following compound : [ 1 ]

6. How would you convert ethanol to ethoxy ethane ? [ 1 ]7. Draw the structure of 4-Methylpent-3-en-2-one. [ 1 ]8. Rearrange the following compounds in decreasing order of the pKb values.

and [ 1 ]

9. How would you account for the following ?(i) Frankel defects are not found in alkali metal halides.(ii) Schottky defect lower the density of related solids.

[1x2]

10. The radius of atom A is 248 pm and it forms bcc lattice. Calculate the edge length of the unit cell.

[ 2 ]

11. Write any two differences between Molecularity and order of the reaction. [1x2]12. A first order reaction is 15 % complete in 20 minutes. Calculate t1/2. [ 2 ]13. Outline the principles of refining of metals by the following methods.

(i) Zone-refining (ii) Mond’s process for refining of Ni[1x2]

14. How would you account for the following :(i) of the d4 species, Cr2+ is strongly reducing while Mn3+ is strongly oxidising.(ii) transition elements can form complexes.

ORHow would you account for the following :(i) there is a greater range of oxidation states among the actinoids than that in the

lanthanoids.(ii) La(OH)3 is a stronger base than Lu(OH)3.

[1x2]

15. Complete the following chemical equations :(i) (ii)

[1x2]

16. (i) Which of the following has higher freezing point and why ? 0.1 M NaCl or 0.1 M glucose.

(ii) 10 mL of a liquid A were mixed with 10 mL of liquid B. The volume of resulting solution was found to be 19.9 mL. What do you conclude ?

[1x2]

17. What are essential and non-essential amino-acids ? Give one example of each type. [ 2 ]18. What happens when D-glucose is treated with the following reagents ?

(i) H I (ii) Br2

[1x2]

19. 200 cm3 of an aqueous solution of a protein contains 1.26 g of the protein. The osmotic pressure of such a solution at 300 K is found to be 2.57 x 103 bar. Calculate the molar mass of the protein.

[ 3 ]

20. Explain the following terms : (i) Electrophoresis (ii) Dialysis (iii) peptisationOR

What is difference between multimolecular and maromolecular colloids ? Give one example of each. How are associated colloids different from these two types of colloids ?

[1x3]

34/1 P.T.O.( 2 )

21. How would you account for the following :(i) White phosphorus is more reactive than red phosphorus.(ii) The N-O bond in is shorter than the N-O bond in .(iii) Sulphur in vapour state exhibits paramagnetism.

[1x3]

22. Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory.(i) (ii)

[1½x2]

23. (a) Arrange the compounds of given set in increasing order of their reactivity towards SN2 displacement1 – Bromobutane, 1 – Bromo-2, 2 – dimethylpropane,1 – Bromo – 2 – methylbutane, 1 – Bromo – 3 – methylbutane

(b) Complete the equations for the following reactions :(i)

[1+2]

(ii)

24. How would you obtain the following :i) Aspirin from phenolii) Benzoquinone from phenoliii) 2-Methylpropan-2-ol from Methyl Magnesium bromide

[1x3]

25. State reactions for the following :i) Aniline does not undergo Friedel-craft’s reaction.ii) PKb of aniline is more than that of methylamine.iii) Although amino group is ortho and para directing in aromatic electrophilic

substitution reaction, aniline on nitration gives a substantial amount of meta-nitroaniline.

[1x3]

26. Write names and draw the structures of the monomers of the following polymers.(i) Buna-S (ii) Nylon-66 (iii) Bakelite

[1x3]

27. Explain the following terms with suitable example of each.(i) Non-ionic detergents (ii) Analgesics (iii) Antacids

[1x3]

28. (a) Define the term molar conductivity. How is it related to conductivity of the solution ? [2+3](b) One-half-cell in a Voltaic cell is constructed from a silver wire dipped in Silver

nitrate solution of unknown concentration. Its other half-cell consists of Zinc electrode dipping in 1.0 M solution of Zn(NO3)2. A voltage of 1.48 V is measured for this cell. Use this information to calculate the concentration of silver nitrate solution used.

OR(a) Explain variation of molar-conductivity with concentration for weak and strong electrolytes.

(b)

i) Construct a galvanic cell using the above data.ii) For what concentration of Ag+ ions will the emf of the cell be zero at 25ºC, if the

concentration of is 0.01 M ? (log 3.919 = 0.53)

34/1 P.T.O.( 3 )

29. (a) Draw the structures of the following molecules :(i) BrF3 (ii) Xe F2

[2+3]

(b) Complete the following equations :(i) Xe F6 + H2O (ii) Cu + conc. HNO3 (iii) Ca3P2 + H2O

OR(a) What happens when

(i) Chlorine gas is passed through a hot concentrated solution of NaOH ?(ii) Sulphur dioxide gas is passed through an aqueous solution of Fe3+ salt ?

(b) Answer the following :(i) bond dissociation energy of F is less than that of Cl.(ii) Iron dissolves in HCl to form FeCl2 and not FeCl3.(iii) Noble gases form compounds with Fluorine and oxygen only.

30. (a) Illustrate the following named reactions :(i) Aldol condensation (ii) Rosenmund reduction

[2+3]

(b) An organic compound with molecular formula C9H10O forms 2, 4-DNP derivative, reduces Tollen’s reagent and undergoes cannizzaro reaction. On vigorous oxidation, it gives 1, 2-benzenedicarboxylic acid. Identify the compound and write all the equations involved in it.

OR(a) Give chemical tests to distinguish between the following pairs.

(i) Benzaldehyde and acetophenone (ii) Phenol and Benzoic acid(b) A compound ‘X’ (C2H4O) on oxidation gives ‘Y’ (C2H4O2). “X” undergoes haloform

reaction. On treatment with HCN “X” forms a produced “Z” which on hydrolysis gives 2-hydroxypropanoic acid.(i) Write down structures of “X” and “Y”.(ii) Write down the equations for the reactions involved.

- - - - - - - - - - -

34/1 P.T.O.( 4 )

ANSWER KEY – 1 (CHEMISTRY)S.No. Value points Marks1 Minimum amount of energy supplied to reactants to convert into products 12 Zeolite 13 Roasting- With excess of air & for sulphide ores

Calcination- Absence or limited supply of air & for carbonate ores .½ ,1/2

4 The steady decrease in the atomic and ionic radii of Lanthanoids in atomic number due to poor shielding effect of 4f electrons

1

5 3- Bromo-2,4-dimethylhex-2-ene 16 By heating ethanol at temp. 413 K in the presence of conc. Sulphuric acid 17 1

8 (C2H5)NH> C2H5NH2 > C6H5NHCH3 > C6H5NH2 19 (i) Due to large size of alkali metals

(ii) Due to decrease in mass1, 1

10 r = √3a/4a = 4r/√3= 4×248/1.732= 572.75pm

1, 1

11 Any two differences 1, 112 k=2.303/t × log [R]0/[R]

=2.303/20 ×log100/85 =2.303×.07058/20 =8.13×10-3

t1/2 = 0.693/kt1/2 = 0.693/8.13×10-3

= 85min

2

13 (i) Impurities are more suluble in liquid state than in solid state

(ii)

1 ,1

14 (i) Eo value for cr3+/Cr2+ is negative (-0.41V) while for Mn3+/Mn2+ is positive (+1.57V)

(ii) Due to vacant d- orbitals& high chargeOR

(i) Due to comparable energies of 5f, 6d,7s orbitals(ii) Due to lanthanoid contraction

1, 1

15 (i) Cr3+ + CO2 +H2O(ii) MnO2 + SO4

2- + OH-1,1

16 (i) 0.1 NaCl due to two ions(ii) –ve deviation

1,1

17 Essential – required for body and not synthesis in body e.g. valineNon essential – synthesis in body e.g. glycine

1,1

18 (i) Hexane(ii)

1,1

19 MB = WB x RT x 1000/ V = 1.26 x 0.083X300 x 1000/2.57 x 10-3 x 20061.022 g/mol

1,1,1

20 (i) The movement of colloidal particles towards oppositely charged electrode in an electric field

(ii) It is a process of removing a dissolved substance from a colloidal

1X3

34/1 P.T.O.( 5 )

solution by means of diffusion through a suitable membrane(iii) The process of conversion of a freshly prepared ppt into a colloidal

solution by adding a suitable electrolyteOR

Multimolecular – colloidal particles are aggregates of atoms or molecules each having size less than 1nm e.g. gold solMacromoleculer- colloidal particles are themselves large molecules e.g. starchAssociate colloidas are possible at higher conc. & kraft temp

21 (i) Red P is less reactive due to its polymeric structure(ii) N-O bond in NO2

- is an average of a single bond & a double bond whereas the N-O bond in NO3

- is an average of two single bonds & adouble bond

(iii) Due to two unpaired electrons

1X3

22 (i) Octahedral, diamagnetic, d2sp3

(ii) Octahedral, diamagnetic, d2sp3½ X6

23 (a) 1-Bromo 2,2-dimethyl propane < 1- Bromo 2- methyl butane < 1- Bromo 3- methyl butane < 1- Bromobutane

(b) (i) C6H5I + N2 + KCl

(ii)

1X3

24 1X3

25 (i) With lewis acid it forms salt(ii) Due to resonance(iii) Anilinium ion is meta directive

1X3

26 (i) CH2=CH-CH=CH2(1,3-Butadiene) + C6H5CH=CH2(Styrene)(ii) NH2(CH2)6NH2(Hexamethylene diamine) + HOOC(CH2)4COOH(Adipic acid)(iii) C6H5OH(Phenol) + HCHO(Formaldehyde)

1X3

27 i) Not contain any ion .e.g. ester of stearic acid and polyethylene glucose.

ii) Which are used to reduce pain e.g. Aspirin iii) are used to removes the excess acid in the stomach . e.g. ranitidine.

1X3

28 a) The Conductance Of The Solution Containing 1 Mole Of The Electrolyte, When Electrodes Are Unit Distance Apart Having Sufficient Area Of Cross-Section To Hold The Electrolyte .

ΛM =ƙ/Mb) Zn(s) + 2Ag+ ――> Zn2+ + 2Ag(s)

E0cell = 0.80-(-0.76) = 1.56 V

E cell = E0cell – 0.0591/n log [Zn2+]/[Ag+]2

1.48 = 1.56 – 0.0591/2 log 1/[Ag+]2

[Ag+] = 0.044 M.

2+3

34/1 P.T.O.( 6 )

OR

a)

b)

(i) Cu (s) |Cu2+(aq) || Ag+

(aq) | Ag(s)

(ii) E0cell = 0.80 – 0.34 = 0.46 V

0= 0.46 – 0.0591/2 log [Cu2+]/[Ag+]2

[Ag+] = 1.597 x 10-9 M.

29 a) (i) BrF3 Bent T shape

(ii) XeF2 linear

(b)(i) XeO2F2 + 4HF(ii) Cu(NO3)2 + 2NO2 +2H2O(III) 2PH3 + 3Ca(OH)2

OR(a)(I) 5NaCl + NaClO3 + 3H2O(II) 2Fe2+ + SO4

2- +4H+

(b)(i) due to small size of F atom lone pair – lone pair repulsion is there(ii) during this process H2 formed which prevent the further oxidation of Fe2+ ion (iii) because oxygen and F are strong oxidising agent due to their small size and high electonegativity

2+3

34/1 P.T.O.( 7 )

30(a) (b) OR (i) iodoform test(ii) sodiumbicarbonate test

(b)

2+3

34/1 P.T.O.( 8 )