LIST OF EXPERIMENTSClass IX

Every student will be required to perform following fifteen experiments during the academic

session.

l. To prepare :(a) A true solution of common salt, sugar and alum'

(b) A suspension of soil, chalk powder and fine sand in water.

(c) A colloidal of starch in water and egg albumin in water and distinguish between these on

the basis of (i) transparency, (fi) filtration criterion, and (iii) stability.

2. To prepare :(a) A mixture(b) A compound

Using iron filings and sulphur powder and distinguish between these on the basis of :

(l) appearance, i.e., homogeneity and heterogeneity(ll) behaviour towards a magnet(ill) behaviour towards carbon disulphide (a solvent)(iv) effect of heat

3. To carryout the following chemical reactions and record observations. Also to identify the type

of reaction in each case.

- (t) Iron with copper sulphate solution in water

(il) Burning of magnesium in air

(iii) Zinc with dilute sulphuric acid

(lv) Heating of lead nitrate

(v) Sodium sulphate with barium chloride in their solutions in water.

4. To verify laws of reflection of sound.

5. To determine the density of a solid (denser than water) by using a spring balance and a measuring

cylinder.

6. To establish the relation between the loss in weight of a solid when fully immersed in

(l) tap water(li) strongly salty water, with the weight of water displaced by it by taking at least two different

solids.

7. To measure the temperature of hot water as it cools and plot a temperature-time graph.

t. To determine the velocity of a pulse propagated through a stretched string/slinky. :

9. To prepare stained temporary mounts of (a) onion peel, and (b) human cheek cells and to record

observations and draw their labelled diagrams.

10. To identify parenchyma and sclerenchyma tissues in plants, stripped muscle fibres and nerve cells

in animals, from prepared slides and to draw their labelled diagrams.

11. To separate the components of a mixture of sand, common salt and ammonium chloride

(or camphor) by sublimation.

12. To determine the melting point of ice and the boiling point of water.

13' To test (a) the presence of starch in the given food sample, and (b) the presence of the adulterantmetanil yellow in dal.

14' To study the characteristics of spirogyra/Agaricrzs, Moss/Fern, pinus (either with male or femalecone) and an Angiospermic plant. Draw and give two identifying features of groups theybelong to.

15' To observe and draw the given specimens - earthworm, cockroach, bony fish and bird. For eachspecimen record :(a) one specific feature of its phylum(b) one adaptive feature with reference to its habitat.

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SCHEil,IE OF EVALUATIMultiple choice type question written test (school based)Hands-on practicals examination (school based)

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bird. For each

separately in water.of common salt, andthese on the basis of

(b) a compound using iron filings

Experiment | (b). To distinguish between the mixture and compound(i) Appearance i.e., homogeneity and heterogeneity

(il) Behaviour towards a magnet(iil) Behaviour towards carbon disulphide (a solvent)(iv) Effect of heat 35

3. CHEMICAL REACTIONS 42

Experiment 1. To study the chemical reaction of iron nail with copper sulphatesolution in water, and to identify the type of this reaction. 42Experiment 2. To study the reaction when magnesium ribbon is burnt in air andto identify the type of this reaction. 44Experiment 3. To study the chemical reaction of zinc with dilute sulphuric acidand to identify the type of this reaction. 4jExperiment 4. To study the reaction when lead nitrate is heated and to identify thetype of the reaction

50Experiment 5. To study the reaction between sodium sulphate and barium chloridein their aqueous solutions and to identify the type of reaction. 53

4. SEPARATION OF THE COMPONENTS OF A MIXTUREExperiment 1. To separate the components of a mixture of sand, common salt andammonium chloride (or camphor) by sublimation.

5. MELTING POINT OF ICE AND BOILING POINT OF WATERExperiment 1. To determine the melting point of ice.Experiment 2. To determine the boiling point of the given sample of water.

CONTENTSTNTRODUCTION

CHEMISTRY SECTION

1. SOLUTION, SUSPENSION AND COLLOIDExperiment 1. To prepare true solutions of commonin water.

salt, sugar and alum separately

Experiment 2. To prepare suspension of soil, chalk powder and fine sand separatelyin water.Experiment 3. To prepare colloids of starch and egg albuminExperiment 4. To prepare a colloid of starch, a true solutionsuspension of chalk powder in water and distinguish betweenthe following :

(l) Transparency(lr) Filtration crirerion

(ili) StabilityExperiment 5. (Test Exercise)

2. MXTURE AND COMPOUNDExperiment | (a). To prepare (a) mixture andand sulphur powder.

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T\TRODT CTIO\

"If I hove to li;e my lift again, I would always remain in my laboratory

for the greatest joy of my lfe to accompltsh original scientffic work."

J.B. Andre Dumas

,seeing experiments being performed, i.e.,'demonstration experiments' are quite important for theof the principles of science. Performing experiment by one's own hands is more important

it involves 'learning by doing'. That is, for a scientific training of 4 young mind a genuiner practice is a must. A laboratory is a workshop where truth of ideas is tested and many

aspects are verified.

coming to the laboratory for practical work, students must be acquainted with certain basic rulesnegulations of the laboratory to enable them to do their practicals smoothly, effectively and more

. Some important instructions for the students are given below :

f,pipment.

It$nrlenl must carry with him / her the following things to the laboratory on every practical turn so thath/SF is well equipped to perform various types of experiments :

Darting the Laboratory

r While coming to the laboratory for practicals, students should check that they are carrying allthe needed equipment mentioned above, in proper working condition.

o Students should also be well versed with the work they are required to do in the practical period.For this they should always enquire from their teacher about the practical work to be done.

o It is very essential that students must reach the laboratory silently within 2 to 3 minutes afterthe previous period bell is over. Your teacher will allot you a permanent working seat in thebeginning of the session.

. Always occupy the seat allotted to you and don't change it frequently until it is otherwiseneeded. This will avoid confusion and unnecessarily running about in the laboratory.

hrnctuality

A surdent should not be absent from his practical class and should reach the laboratory as soon as thepcriod starts. This will enable him / her to keep his / her practical work up to date. Once a praqtical classfrr missed, it is difficult for the teacher to repeat the instructions for one student alone.

Dncipl ine

A student is required to maintain silence in the laboratory and listen the instructions carefully.

Care of Instruments and Apparatus

r The instruments, glasswares or any other equipment that you are going to use in the laboratoryshould be kept at proper and specified place to avoid any confusion and disturbance. Alwaysreplace the apparatus back to its original position after use.

o Any glassware or apparatus that you use, should be washed and cleaned before it is kept.Instruments must be handled carefully. Carelessness will not only damage the instrument orappa.ratus but may also cause injury to the students.

Instructions

l- Laboratory notebook 2. Manual of practical science 3. Auxiliary notebook

4- A pencil, preferably HB 5. Eraser 6. Scale

Rr.r l rd \ la intenance

It is a must for everyduring the practical. For

student to maintain

this purpose, buy aa practical record book

good quality record fileto note down

as suggested

the observ

Generally, you get two practical turns in a week. Whatever work is done on

should.be duly recorded in your file on the same day or the next day at the most.

checked by your teacher on the same day or on the next turn.. You must carry the

which you may not be allowed even to enter the laboratory.

*l'

by your pract

', Siorn some marks are reserved for the record file in the An.nual Practical Examination,I ,, it must be maintained in neat and tidy form.

the day of prYou must alsopractical file, fai

A neat and systematic recording of the experiment in the practical file is very important in achieving

success of the'experimental investigations. The students may write the experiment under theheads in their fair practical notebooks.

It may also be recorded in a slightly different way as may be suggested by the teacher.

Itht tfr* Left Hand PaSe (Blank Pagel

\i;tu ,rt,,r, Wrruih, i

Date . . . . . . . . . . . . . Experiment No. . . . . . . . . . . . . . Page No. . . . . . . . . . . . . .

1. Aim/Object/ Assignment

2. Diagram

3. Observations

4. Calculations

5. Result/Results with percentage error.

iir,-rrRight Hand Page tRuled Page) |

(To be written only in ink)

Date . . . . , . . . . . . . . Experiment No. . . . . . . . . . . . . . Page No. . . . . . . . . . . . . .

1. Aim / Object/Assignment

2. Requirements

3. Theory / Basic principles

4. Procedure/Method

5. Precautions

6. Sources of error

7. Results/Discussion

nn the observatibd by your

Sramination,

rhe day ofYou must also gpractical file, fr

qant in achievingunder the fol

E teacher.

ge No.

lc No.

c ffiar approved eye protection and laboratory coat or apron while working in the chemistryltratory. But never wear contact lenses in the laboratory.

rffu.wrer eat. drink or smoke in your laboratory.

rffiewr perform an unauthorised experiment.

lffihmrt proper supervision never work in the chemistry laboratory.

Wafting odour

fCH- J. Proper heating Fig.2. Correct way to know the odour.

rT*e proper care while heating, as shown in Fig. 1. Never heat a liquid in a test tube that isFimfd toward you or another student.

i m{crrcr inhale gases or vapours. If you have to know the odour of a gas or vapour, use your hand'm waft a small sample toward your nose as shown in Fig. 2.

o Ba careful with glass equipment. When inserting a glass rod or tube or thermometer through alffier cork, lubricate the glass and protect your hands with a cloth towel, and use a gentletnisting motion as shown in Fig. 3.

iGede ts-ist

Fig. 3. Correct way of inserting Fig. 4. Proper way of mixing.a glass tube in a cork.

r Exercise proper care in mixing chemicals. Always pour acid into water for dilution as shownin Fig. 4 and never the reverse way.

r Know the location and use of emergency equipment like fire extinguisher and first aid box, etc.

a Do not over react

trn case of any accident, ask immediately for help and keep calm.

r Be prepared to help someone else involved in an accident, but do not get in the way of ;'our

teacher when he or she is attending to the emergency call.

r Never under react

Any chemical contact may be harmful. Wash the affected area immediately and properly with

water, and get the first aid treatment.

A. Gluss cuL Remove the visitrle glass pieces from the affected part. Stop bleeding by washing

with ice water and dettol and apply mercutochrome bandage.

B. Heat bwrns. Apply common salt on the affected pafi due to dry burn (never apply salt if bristles

have formed) remove the salt after five minutes and then apply Silver Sulphadiazine Cream.

C. Acid burns. Wash thoroughly with water and a dilute solution of sodium bicarbonate (baking

soda) then with water. Soak with dry cloth and apply some nongreasy antiseptic ointment.

D. Atkali burns. Wash with water, very dilute solution of acetic acid and then again with water'

Dry with cloth and apply nongreasy antiseptic ointment.

E. Eye injuries. Wash the eye properly with cold water, then with 2Vo soltttron of boric acid and

contact your doctor immediatelY.

Flowing garments, long flowing hair, high heal shoes are hazardous in a laboratory.

Follow the instructions of your teacher and sign the safety agreement.

I n. t r t rct i r rn

S:rfefv Requiremenfs in a Laboratory

o Adequately ventilated fumehoods

r Fire extinguishers

o Eye wash fountain

a First aid box

lurf'ef] Agreement

l - ,

i I have read the safety rules, and I agree to follow them sincerely.i

j . Signature of the studentt

I Name Roll No.

I

i class

Sisnature of the teacher

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hsrructions for Performing Experiments in ph.vsics Laboratorv

the way of ;

nd properly wit

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r a laboratory.I

r Before performing an experiment, the student should first thoroughly understand the theory ofthe experiment. The object of the experiment, the kind of apparatus needed and the procedureto be followed should be clear before actually performing the experiment. The difficulties anddoubts, if any, should be discussed with the teacher before hand.

o The student should check up whether the right type of apparatus for the experiment to beperformed is given to him or not.

r All the pieces of apparatus should be arranged on the table in proper order. Every apparatusshould be handled carefully and cautiously to avoid any damage. Any accidental damage orbreakage of the apparatus should be immediately brought to the notice of the concemed teacher.

o hecautions meant for the experiment should be actually observed white doing the expeTiment.r All observations should be taken systematically and should be honestly recorded on the fair

record book.

r Repeat every observation a number of times even though their values may be exactly the sameeach time. The student must bear in mind the proper plan for recording the observations.Recording in tabular form is essential in most olthe experirnents.

r Calculations should be neatly made using log tables. The degree of accuracy of measurementof each quantity should always be kept in mind so that the final result does not show anyfictitious accuracy. The result obtained should be suitably rounded off.

I s'herever possible, the observations should be represented with the help of a graph.r Alq,a].s mention the proper unit (if any) with the result.

and its Advantages

r A graph is the most convenient way of showing how the physical quantities vary with respectto each other. Two varying quantities called the variables are essential features of a graph. Thequantity which is made to change at will, is known as the independent variable and the otherqrtantity which varies as a result of this change is known as dependent variable.

r The most important advantage of a graph is that the average value of a physical quantity underinvestigation can be got very conveniently from it without resorting to lengthy numericalcomputations. Another important advantage of graph is that some salient features of a givenexperimental data can be seen visually. For example, the points of maxima, minima or inflexioncan be easily known by simply having a careful look at the graph representing the experimentaldata. These points cannot so easily be concluded by merely looking at the data.

5md 6 show two different $aphs representingthe same experimental data (table l) of the samewinble quantities. The graph shown in Fig. 5 is better *d

-or" accurate representation of the

mental data than the graph shown in Fig. 6. This difference arises because of Jne specific choiceqtelg5 for the two axes along which the two variables are plotted. For the graph of Fig. 5 the choicescale is proper whereas for the graph of Fig. 6 an improper scale has been choseln.

Set No. I 2 J 4 5

Variable'x' (IndePendentl 8.33 8.75--.-5.80

9.15 9.50 9.88

6.75 7.60 8.50Variable'y' (DePendent) 4.80

F--

Table 1. Data Independent and Dependent Variables

Thefo1lowingpointswi1lbefoundusefu1fordrawingapropergrapho Examine carefully the experimental data and note the range of variations of the two variables

to be plotted. Also examine the number of divisions available on the two axes drawn on the

graph paper. After doing so make a suitable choice of scales for the two axes keeping in mind

that the resulting gropi should practically covir almost the entire portion of the graph paper

as shown in Fig. 5.

l , i iPlot of y vs. x

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Variable (Units) ----+

Fig. 5. Proper choice of scale gives a good graph'

I Write properly chosen scales for the two axes on the top of the graph paper or at some suitable

place. Draw an alrow head along each axis and write the symbol used for the corresponding

variable along with its unit. Also write the values of the respective variables on the divisiont

marked by dark lines along the axes'

r After plotting the points encircle them. Draw a freehand smooth curve passing through tlrt

maximum number of pointr. Owing to errors occurring in the observations, some of the point'

may not fall exactly on the freehand curve' So while drawing a smooth curve' care should h

exercised to see that such points are more or less evenly distributed on both sides of tht

curve.

o when the plotted points happen to lie almost on a straight line, the straight line should be draw

using a sharp pencil and a straight edged ruler. care should be taken to ensure that the straigh

line passes through fhe maximum number of points and the remaining points are almost evenl'

distributeil on both sides of the line'

i

he two variales drawn on the

I keeping in mitthe graph

t .tr at some sulltuk on the divis

k** throughlnme of the

!ve, care shouldiboth sides of

re should bepe that the strai

o When the plotted points do not appear to lie on a straight line, a smooth curve is drawn withthe help of a device known as French cLtrve.If French curve is not available, a thin flexiblespoke of a broom can be used for drawing a smooth curve. To make the spoke uniformly thinthroughout its length, it is peeled off suitably with a knife. This flexible spoke is then heldbetween the two fingers of left hand and placed on the graph paper bending it suitably with thepressure of fingers in such a manner that spoke in the curved position passes through themaximum number of points. The remaining points should be more or less evenly distributed onboth sides of the curved spoke. In this bent position of the spoke, a smooth curve along thelength of the spoke is drawn using a sharp pencit.

246810121416

Variable (Units) -)

Fig. 6. Improper choice of scale gives a poor graph.

o A proper title should be given to the graph thus plotted

o Preferably a millimetre graph should be used to obtain greater accuracy in the result.

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ffi Experiments in Biorogy Laboratory

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Before coming to the biology laboratory for practical *o+' students

basic rules *o ,"euiu-ilon. or It" rauor.atlrv I 1* :*T,::*Ji:]practicals smoothlY, effecti

baslc rures '1'u rvbu ' structions for the students are

'and more efficiently' Some important ffigiven below :

EquiPments' lPrrrtrrro . ^L^ r^L :t ical tum. so

A student musr carry with him the following things to the laboratory on every pra(

h" ;-;;ii equipped to p"'fo'm various types of experiments :

1. LaboratorY notebook

2' LabotatorY manual

3. AuxiliarY notebook

4. A Pencil, PreferablY HB

5. Eraser

6. Scale

7. Needles (two) ;

8. Blade

9. Scissors

-10' ForcePs (00 No')

11. Brush (0 No')

12. A small cotton naPkin

must be acquainted with

il' sln[ilc

Srdr of

Wme5m do ocffiB in

Srrdr of

II

IMethod of Writing

Usearuledpaperforwrit ingashortparagraphor.thepointsoftheworkyouhavedoneinthel|you wilr arso be required to do the same even in ttre examination. The Aim or objective of {

experiment should b-e clearly Td""Y. You are ur',o

'"qoi'1J to rTite the Materials reuuir{

procedure, observations, Results and precautions dep".riirrg upon the nature of the experiment'l

o First

. Tr.vI

r Drarl

o Avt*

r Alwl

Spotting

Sketching and Writing - i c,^ Spotting is in

Diagrams should arways be drawn on the drawing sheet of the record file' Draw large and nl'

diagrams but they should be proportionate to the size of the paper. Dr1ry_ dilerams in the centre of i o Alwa

page so thar enough;n;;"'rh"'sides is available for rabe[ing. IVft ile labeiling, rines shoul'd not *t o Drar

each other. A boundary line or margin should always be drawn all along the paper. Always put the dr

of the experimenr on the top reft corner ";;"

pug". iJ." black read p"nrit while maki"g u '*tt"tt'

Lego e only

of the sketch should also be written'

A sample page of your record file is shown below.

with certain

, effectivelj

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IIf

I

t.

tlmvrFiFkF"tl

iturn, so thaf

done in theof

requexpefiment.

large andthe centre ofshould notays put the

a sketch. Le

Date

Aim :

Materials required :

Procedure :

Observations :

Precautions :

L.S. of collenchyma

Sample page of record file.Studv of Slides

While studying slides under the microscope, do not disturb the slide focussed by the teacher. In caseyou do not follow, seek the help of your teacher. You can move the fine adjustment screw to bring theslide iri sharp focus.

Study of Museum Specimens

o First carefully study the characteristics of the specimen from the book.

o Try to find out these characteristics in the specimen.

o Draw a line diagram of the specimen. If needed, draw more than one view of the specimen.

o Avoid shading of the diagram.

o Always write classification for the entire specimen.

Spotting

Spotting is important in Biology Practicals. For this, remember the following points :

o Always write the spot number

o Draw a rough but correct and well labelled diagram of the spot.

o Only important and interesting fearures should be given.

A sample page of your record file is shown below.

atf,;

rFhintedh**trv[ :tf

t

with, effec

hcticat tum, so t

bave done in the lal

;or Onjective of th

fl[aterials requirelbf the experiment.

ls in the centre of tl

Elrcs should. not cro

p- Always put the da

F"g u sketch. Leger

t

tivel

r Spotting

Qnn++inr i . i -^^*--

pDraw large and ,r, Spotting is important in Biology Practicals. For this, remember the following points :

Date-

Aim :

Materials required :

Procedure :

Observalions :

Precautions :

L.S. of collenchyma

Sample page of record file.Study of Sl ides

While studying slides under the microscope, do not disturb the slide focussed by the teacher. In caseyou do not follow, seek the help of your teacher. You can move the fine adjustment screw to bring theslide iri sharp focus.

Study of Museum Specimens

o First carefully study the characteristics of the specimen from the book.

o Try to find out these characteristics in the specimen.

o Draw a line diagram of the specimen. If needed, draw more th,an one view of the specimen.

o Avoid shading of the diagram.

'o Always write classification for the entire specimen.

o Always write the spot number.

o Draw a rough but correct and well labelled diagram of the spot.

o Only important and interesting feafures should be given.

:it

3tii

Lab Maintenance

c AlwaYs keeP Your seat clean'

oDonotspoi l i te i therwithstainolanyothercolouredmater ia l .

o Keep some paper undemeath while working with a stain'

e Do not scratch the table either'

oAfterdoingthepracticalsthrowthewastesonlyinthedustbinlyinginthecornerofthelab.

c stop doing the work before 2 to 3 minutes of the bell and clean your seat'

o Replace each and every thing back to its original position before you leave the lab'

o Neither talk loudly nor run around in the lab'

oCol lectal l themater ia lsonyourseatwiththehelpofthelabassistant '

o Students usually are in the habit of playing with the microscope by moving the screws up and

down. This is very harmful. Learn the correct use of the microscope before you touch it' Always

rememberthatmicroscopeisaninstrumentandnotatoytoplaywith.

tr. To prepa(a) At(b) Ar(c) At

bas(r(n(tn

2. To prepa

(a) At

(b) Ar

Usi( t

( ir( i i t( it'

3. To carn'oreaction il

(t) Iror(ii) Bur

(iii) ha(n') Her(r')' So<

{. To sepan(or camph

5. To detern

10

upl

Alw

rof thelab.FtI

i,n" uu.rh

tf

the screws

b touch it.r'r

LIST OF EXPERIMENTS

1. To prepare :

(a) A true solution of common salt, sugar and alum

(b) A suspension of soil, chalk powder and fine sand in water

(c) A colloid of starch in water and egg albumin in water and distinguish between these on thebasis of :

(i) Transparency(ii) Filtration criterion

(iii) Stability

Tr;repare :(a) A mixture(D) A compound

Using iron filings and sulphur powder and distinguish between these on the basis of :(i) Appearance, i.e., homogeneity and heterogeneity

(ii) Behaviour towards a magnet(iii) Behaviour towards carbon disulphide (a solvent)(iv) Effect of heat

, ,To carryout the following chemical reactions and record observations. Also to identify the type ofmion in each case.

(t Iron with copper sulphate solution in water.

(ir) Burning of magnesium in air

1;;i'1 7]nc with dilute sulphuric acid

(ir') Heating of lead nitrate(r) Sodium sulphate and barium chloride in their solutions in water.

To separate the components of a mixture of sand, common salt and ammonium chloride(a camphor) by sublimation.

To &termine the melting point of ice and the boiling point of water.

FGLASS WARES AND OTHER ACCESSORIES

EDED IN CHEMISTRY LABORATORYCOMMON

NE

F ffif t t . tt t t ti l t lf t t li l [ rl t f lLJ LJ

Test tube Boiling tube

Test tube hoider

\JTest tube brush

Round bottom flask

C)w{}

I jLJReagent bottle

WChina dish

ffiPestle and mortar

wWatch glass

Test tube stand

\ /

Rf lIxI I

ffiBurner

mlEl t lH t lH l l

Thermometer

o

], E:of

a

a

a

a

Funnelf t

HilfqRt1FIEIl : l

t=lHEIF={t=lE]t=|l= l

UPipette

BeakerConical flaskFlat botlom flask

Tripod stand

Graduated cylinder

I

I!

SOLUTION, SUSPtrNSTON ANN COLLOID

:;:;*irffi<Y To prepur"e true solutions af ceftrlnon salt, sugar and aluw separately in water.' Cotmrloti salt (sodiurn chloride), sugar, alurn, distilled water, measuring cylinder,

' r ' r : r i i . g lass rods (3) and watch giasses (3).il piace etf beerker the solution may also be prepared in boiling tube or test tube or plastic

: - , --" . i , i ' , .ect as tea cup).

\\hett a stnall quantity of a solid such as coillmon salt (sodium chloride, NaCl) or sugar or'Llriul is aCded to a glass of water and stined, the solid dissolves. As a result of this activity, hotnogeueous material is obtailed. This homogeneous material is a true solution.Lr the solution the substamce dissolved (such as cotrunon salt or sugar or alun) is called solute.drd water is called solvent.

-\ true solution is transparent and stable.

The solute and solveut cannot be separated from the true solution by the method of filtration.

, Lt general a tme solution is called solution.

i r i f l l r

Take a cleem beaker. Paste a paper on it. On this pasted paperu'rite your Roll No. and the paliculars of the solution to beprepared, e.6;., Comrnon salt + Water.

Take about 20 mL of distilled water in the beaker.With the help of a spoon add about 1 grarn of comrnon salttr the water taken in the beaker.

Take a clean glass rod (ils ends sltould be stnooth') and stir theu'ater il beaker so that salt dissolves cornpletely. Cover thesolution with a watch glass to protect it frorn dust.

Now a true solution of corunon sait in water is ready.

,,, i , i t l i l . . i i i ;r i i : l l '+t:.s.iu:: i i ' ,1'1ir". ::rci;:r.:;.t{ i*lr: i i l i : t fr*{t{. s*gtr;rt!c:l: i_, : . ' i : i : ' t r , r r : :1._1.

T;ke a clean beaker. Paste a paper on it. On this pasted paperwrite your Roll No. ard the particulars of the solution to beprepared, e.9., Sugar + Water.

Take about 20 rnl- of distilled water in the beaker.

Grind sugan into fine powder (Fine powtler will clissolvet'aster)

With the help of a spoon add about 1water taken h the beaker.

gram of sugar in the

13

Fig. 1. Prepttrotion of a solutiottof common salt in water

F-ig. 2. Preparation of asolution o.f sugar in wnter

bn-

Water

Sugar

Burner

tii"--,",-",.--; spbonr , t , ]

i .',' I Glass rod used

- - . -^ i

r :o Take a clean glass rod (its encls should be smooth) and stir the water in beaker so that sugar

dissolves completely. Cover the solution with a watch glass to protect it from dust.

o Now a true solution of sugar in water is ready'

3. Experimental procedure for the preparation of a true solution of alum in water.

o Take a clean beaker. Paste a paper on it. On this pasted

paper write your Roll No. and the particulars of the solution

to be prepared, e.g., Alum + Water'

o Take about 20 mL of distilled water in the beaker'

o Grind bigger particles of alum into smaller pafiicles and

finally make fine powder (Fine powder will dissolve faster)

r With the help of a spoon add about 1 gram of alum in the

water taken in the beaker'

o Take a clean glass rod (its ends should be smooth) and stir Fig. 3. preparation of athe water in beaker so that the solid alum dissolves solution of alum in watercompletely. cover the solution with a watch glass to pfotect

it from dust.

o Now a true solution of alum in water is ready'

Sources of Errors and Precautions

e For recognizingthe type of solution. its particulars should be mentioned on the beaker or tesl

tube.

o The solid solute should be powdered so that it dissolves faster.

o The ends of the glass rod should be smooth to avoid any chance of breaking of the glasr

beaker or test tube.

o Solute should be added into water carefully'

c Stirring should be done in such a way that the glass rod does not strike with beaker (or tes' tube).

o The glass rod must be cleaned thoroughly before using it to stir the other solution'

VIVA VOCE

T. What is the aim of your experiment ?

S. The aim of my experiment is to prepare Solutions of common salt, sugar and alum separatel'

in water.T. What is common salt and why is it called so ?

S. The chemical name of common salt is sodium chloride. Its formula is NaCl. It is calls

common salt because it is a coffImon food ingredient'

T. Name two other salts ?

S. Pbtassium chloride (KCl) and sodium sulphate (NarSO/'

T, Which type of sugar you have used for the preparation of solution ?

S. Cane sugar (C'HrrOtt)'

T. What is alum ?

s. Alum is a double salt of potassium sulphate and aluminium sulphate. Its formula i

KAl(SOt2.r2H2O.T. What is the significance of T2H'O in alum ?

S. It is called water of crystallization.

Spoon

Glass rodas stirrerBeaker

Water

T. Can 'S. Alum

T. Wicl

S. Comr

T. Hox'

S. (t) Nr(rr) K

T. You l,

S. In aqT. lWicl

S. SugarT. Wftr ' ,

S. The rthe gr

T. Arll rS. An ar

stron€T. II'har

S. Aboul

T. l*hatwoter

s. 66.67T. Hou'

S lIass

T. Inassolute

S. IIassT. Hou' ,

S. This :T. Hov'

S.Bvm

T. Hov' ,

S. I t isr

T. "/rrsn-fiS Mass

T. llrhar

S. A sohconsulsoluti<

useo

I4

in rr ater.

.4/#t-*}

sp'oon

:alier so thatfrom dust.

Glass rod-------:-as stirrer

(- Beaker

$. # Water

T. Con you tell some uses of alum ?S Alum is used as antiseptic, in dye industry and in the purification of water.T. Wich of sugar, common salt and alum will ionize in aqueous solution ?S Common salt and alum will ionize in aqueous solution.T. How ?S. (t) NaCl (aq) -+ Na+ (aq) + Cl- (aq)

(tt) KAI(SO a)2 @l) --> K+ (aq) + Al3+ (aq) + 2SOo2- (aq)T. You have not written the. molecules of water of crystallization with aLum ?S" In aqueous solution the water molecules of crystalli zatron pass into the solution.T. which of common salt, sugar and alum is highly sorubre in water ?S. Sugar is highly soluble in water.T. Why is the solubility of sugar in water very high ?S. The molecules of sugar (CnHz2Orr) occupy the space between HrO molecules. Thus they fill

the gaps and dissolve in large quantity.T. Any evidence of your answer ?S. An aqueous solution of sugar is highly viscous. In the solution the molecules of sugar bind

strongly with HrO molecules and therefore, the flow of the solution is restricted.T. What is the solubility of sugar in water at room temperature ?S. About 200 g of sugar can be dissolved in 100 mL of warer.T. What is the mass percentage of sugar in a solution containing 200 g of sugar and 100 g of

water. ?5.66.677o.T. How do you know ?

S. Mass Trage of sugar = Mass of supar

\ ." ;i'u4j- Atum

lrepar61i611 o7 o

6 alunt in water

n the beaker or

ealiing of the gl

uith beaker (or

er solution.

and alum separate

Ete. Its formula

x 100Mass of sugar + Mass of water

_ 200g t00o= zoo r;a* x 100 = iofi x 100 = 66-67

T. In a solution if the mass percentage of solvent is 65, then what is the mass percentage of thesolute ?

S. Mass Toage of solute = 100 - Mass voage of solvent = 100 - 65 = 35.T. How will you prepare 50 g of an aqueous solution having I0 mass percent of common salt ?S. This solution will be prepared on dissolving 5 g of common salt in 45 g of water.T. How will you measure 45 g of water ?s. By measuring 45 mL of water with a graduated measuring cylinder.T. How can you say that the mass of 45 mL of water is 45 g ?S. It is assumed that the density of water is 1.00 ginl- ut room temperature.T. Justifi you answer that 45 mL of water - 45 S.S. Mass of water = Volume of water x Density of water

= 45 rnl. x 1.00 glrnl_ = 45 g.T. What is a saturated solution ?S. A solution in which maximum amount of solute is dissolved in a given mass of solvent at a

constant temperature and constant pressure is called a saturated solution. In a saturatedsolution more solute cannot be dissd'lved further.

I

15

_".n

L***#/h water.

, Glass rod:---as stirrer

<- Beaker

[ €- waterilL -if-ab€-- Alum

heparation of a

$ alum in water

!

i

h the beaker or

raking of the

*

nrith beaker (or

t

hd alum separateF

p NaCl. It is cal

T- Can you tell some uses of alum ?lL Alum is used as antiseptic, in dye industry and in the purification of water.T- Which of sugar, common salt and alum will ionize in aqueous solution ?S. Common salt and alum will ionize in aqueous solution.T. How ?S (t) NaCl (aq) -+ Na+ (aq) + Cl- (aq)

(tt) KAI(SO )2 @l) -+ K+ (aq) + Al3+ (aq) + 2SOo2- (ag)T- You have not written the molecules of water of crystallization with alum ?S- In aqueous solution the water molecules of crystalli zation pass into the solution.T- wich of common salt, sugar and alum is highty soluble in water ?S. Sugar is highly soluble in water.T. Why is the solubility of sugar in water very high ?S- The molecules of sugar (CDH22O1) occupy the space between HrO molecules. Thus they fill

the gaps and dissolve in large quantity.T. Any evidence of your answer ?S. An aqueous solution of sugar is highly viscous. In the solution the molecules of sugar bind

strongly with HrO molecules and therefore, the flow of the solution is restricted.T. What is the sotubility of sugar in water at room temperature ?S About 200 g of sugar can be dissolved in 100 mL of warer.T- What is the mass percentage of sugar in a solution containing 200 g of sugar and 100 g of

water. ?5.66.677o.T. How do you know ?

S. Mass %age of sugar = Mass of susarMass of sugar + Mass of water x 100

_ 200g tooo= )oo 1+6* x 100 = 3oG x 100 = 66'67

lT- In a solution if the mass percentage o.f solvent is 65, then what is the mass percenlage of the

solute ?s. Mass Toage of solute = 100 - Mass voage of solvent = 100 - 65 = 35.T. How will you prepare 50 g of an aqueous solution having l0 mass percent of common salt ?S. This solution will be prepared on dissolving 5 g of common salt in 45 g of water.T. How will you measure 45 g of water ?S. By measuring 45 mI- of water with a graduated measuring cyrinder.T. How can you say that the mass of 45 mL of water is 45 g ?S. It is assumed that the density of water is 1.00 gi^1, ut room remperature.T. Justtfy you answer that 45 mL of water - 45 S.S. Mass of water = Volume of water x Density of water

= 45 rn], x 1.00 glrnI_ = 45 g.T. What is a saturated solution ?S. A solution in which maxiinum amount of solute is dissolved in a given mass of solvent at a

constant temperature and constant pressure is called a saturated solution. In a saturatedsolution more solute cannot be dissd'lved further.

Ete. Its

!

i

i

I

formula d

l5

T. Give examples of practical utility of saturated solutions ?

S. Saturated solutions of salt and sugar find practical utility in domestic work to preserve

o pickles

r fiuit jams

o chutaneYs

T. What is unsaturated solution ?

S. It is a solution in which more solute can be dissolved'

T. The mass percentage of a solute in a saturated aqueous solution is 25. A new solution is

prepared by dissolvin7 50 S of the same solute in 200 g of water. Is this solution shturated ?

S. This solution is not saturated.

T. Why and how ?

S. A 25Vo solution means 25 g solute is present in 100 g of solution. But in a solution containing

50 g of solute in 200 g water, the mass Vaage of solute is 20 which is less than 25. Hence

the new solution is unsaturated'

Mass of solutex 100Mass Toase of solute =

Mass of solute + Massof water

' 50g 50g= soff iCx100=ff ix100=20

T. Mention some areas where solutions find their uses?

S. Solutions find their uses in industries, laboratories and in medicines'

T. Mention a use of solution in medicine ?

S. Saline glucose solution is administered to a patient who is suffering from dehydration'

T, Can you tell one use of alum as medicine ?

S. Alum is applied t0 stop bleeding due to minor cuts on skin.

T. Name some solvents other than water ?

S. Ethanol (ethyl alcohol), benzene, carbon tetrachloride and acetone.

T. Name a solvent which is used to remove nail polish ?

S. Acetone

T. W'tat ts the general name of solutions prepared in water ?

S. Aqueous solutions.

T. Name some solid solutions ?

S. (i) Copper in gold (il) Silver in gold (iii) Cu + Zn (Brass) (iv) Copper + Tin (Bronze)'

T. Give an example of an aqueous solution in which gas is dissolved ?

S. Carbon dioxide dissolved in water in cold drinks'

T. The last question.

S. What is that sir/madam ?

T. Why do you use the term true solution for solution. Is there any solution called false solution

S. (Smiles! and comments good question)'

T. (Laughs) But what is the answer of my question ?

S. Some times colloids are also called as colloidal solutions. Therefore, to avoid confusion th

term true solution is used for a solution'

\nn. To prqRequirement

nrls- water.

lusic Principleso When a

shaken, Ir The syst

particlesr The solit

suspensicr The susp

1. Erperirneno Take a cl

write youprepared

r Take a srsoil.

r Powder dr With the

in the beo Add abouo Stir the nr As the bi

from ther Mark the

l. Experimenlr Take a clr

write yourprepared-

r Take a stchalk.

r Powder tho With the I

in the bear Add aboul

beaker.r Stir the mr As the bi5

from the I

r Mark the

-1. Experimenr Take a clr

particulars

t6