Preface
SCERT is a premier organization established for quality improvement in the field of
Education. It conducts training programme, orientation programme, refresher courses,
workshops, seminars and development of course material for Principals, Lecturers, TGTs
and Lab. Assistants.
The present module in the form of supplementary booklet has been prepared for the
Lab. Assistants of schools of Directorate of Education to aware them with the latest changes
in syllabus of secondary science practicals carried out by CBSE.
In present scenario of CCE pattern the practical exam plays a very important role in
formative Assessment. The present booklet has been framed to comply with the guidelines
of changed syllabus of Science Practicals. The booklet has been prepared to develop an
attitude of self confidence and to clear scientific concepts of changed practicals in Lab
Assistants.
This booklet is in continuation of previous edition of manual. It provides some
guidelines for effective performance, development of skills and personality of Lab Assistants.
This booklet has been made possible because of active participation of many people.
I wish to thank to the team of Advisors and experts to provide their valuable suggestions
in preparing this booklet. Mrs. Dr. S.V. Malik, coordinator SCERT alongwith her team
members worked with her sincere effort and spirit of devotion in the limited time schedule.
Their extra ordinary commitment and efficiency for completing this booklet is really
appreciable.
I sincerely hope that this booklet will enable our lab assistants to make the process of
practicals more joyful, interactive and real activity based.
Dr. Pratibha Sharma
J. Director
1
Introduction
Science laboratory is a place where the students test their theoretical knowledge
practically for its validity or truthfulness. They get opportunity to learn the science by
performing practicals. A science student can't learn without a laboratory where the students
gain hands-on-practical experience which enable them to attempt MCQs in exams.
It is a very significant place where the necessary equipments, chemicals and required
facilities are available, which are needed by a science student to perform the experiment.
A lab assistant is the person who not only acts as a guide or a patron but also a
caretaker of tender minds of young and emerging future scientists. They should present
themselves as a role model before the students.
The present supplementary Booklet of Lab. Manual for Lab. Assistants enables them
fully aware with latest changes in secondary science practicals. These changes could not
be incorporated in the previous edition of the manual Two practicals, one from Chemistry
and Biology each for class IX and one from chemistry for class X have been introduced in
this booklet. The methodology of these practicals has also been given in the booklet. They
should also gain the proper knowledge and inhand practice of all experiments as well as
other aspects of science.
Since the Lab. Assistants have already been provided previous edition of manual
containing the detailed guidelines for setting-up of Laboratory, Deptt. of Education circulars
and other important informations., some other additional informations, guidelines and useful
content is further being provided for their reference.
This booklet has been developed with main objective to enable them with latest
changes and to provide them inhand practice for effective management and control on lab
activities.
In case they feel any difficulty in handling the equipments or behaviour of students
etc., they should not hesitate to consult their teachers. For enhancement of quality of practical
work in the laboratory, they should always co-operate with their teachers as well as the
students.
Any suggestions for improvement of science practical skills, critical ideas and
innovative approaches for betterment of science education will be highly appreciated.
Dr. S.V. Malik
Coordinator
2
Changes in Practical List of Class IX - X Science
According to the syllabus of CBSE 2010-11, there are some changes in the Practicals
of IX and X, the changed list of Practicals for previous and Present years are given below:
Class - IX
Experiment No.
3.
13.
2009 (Previous)
(Present) 2010 & 2011
To study the extent of cooling
caused by evaporation of the
following liquids, using a
thermometer, also to arrange
these liquids in the increasing
order of the extent of cooling
produced
i) Water
To carry out the following chemical
reactions and record observations.
Also identify the type of reactions
involved in each case.
i) Iron with copper sulphate
solution in water
ii) Burning of Magnesium ribbon
in air.
ii) Alcohol
iii) Ether
iii) Zinc with dil. Sulphuric acid.
iv) Heating of lead nitrate.
v) Sodium sulphate with Barium
chloride in the form of their
solution in water.
To test (a) the presence of starch in
the given food sample (b) the
presence of the adulterant metanil
Yellow in dal.
To observe the onion peel cells.
Placed in Hypertonic solution
under the microscope and draw
labelled diagram of the same.
Class - X
Experiment No.
13.
2009 (Previous)
(Present) 2010 & 2011
To prepare SO2 gas, observe its
following properties and draw
inferences in respect of
i) Odour
ii) Solubility in water
iii) Effect on litmus paper
iv) action on acidified
K2Cr2O7 solution
To perform & observe the following
reactions & classify them into :
i) Combination reaction.
ii) Decomposition reaction.
iii) Displacement reaction.
iv) Double decomposition reaction.
1. Action of water on quick time.
2. Action of heat on FeSO4 crystals.
3. Iron nails kept in CuSO4 solution.
4. Reaction between Na2SO4 and
BaSO4 solutions.
3
Practicals List of Experiments Class-X
1.
2.
3.
To find the pH of the following samples by using pH paper/universal indicator.
i)
Dilute Hydrochloric acid
ii)
Dilute NaOH solution
iii)
Dilute Ethanoic acid solution
iv)
Lemon juice
v)
Water
vi)
Dilute Sodium Bicarbonate Solution.
To study the properties of acids and bases HCI & NaOH by their reaction with
i)
Litmus solution (Blue/Red)
ii)
Zinc metal
iii)
Solid Sodium Carbonate
To determine the focal length of
a)
Concave mirror
b)
Convex lens
by obtaining the image of a distant object.
4.
To trace the path of a ray of light passing through a rectangular glass slab for different
angles of incidence. Measure the angle of incidence, angle of refraction, angle of
emergence and interpret the result.
5.
To study the dependence of potential difference (V) across a resistor on their current (I)
passing through it and determine its resistance. Also plot a graph between V and I.
6.
To determine the equivalent resistance of two resistors when connected in series.
7.
To determine the equivalent resistance of two resistors when connected in parallel.
8.
To prepare a temporary mount of a leaf peel to show stomata.
9.
To show experimentally that light is necessary for photosynthesis.
10. Carbon dioxide is given out during respiration.
11.
To study (a) binary fission in Amoeba and (b) budding in yeast with the help of prepared
slides.
12. To determine the percentage of water absorbed by raisins.
4
13. To perform and observe the following reactions and classify them into :
i)
Combination Reaction
ii)
Decomposition Reaction
iii)
Displacement Reaction
iv)
Double Displacement Reaction
1.
Action of water on quick lime.
2.
Action of heat on Ferrous Sulphate crystals
3.
Iron Nails kept in copper sulphate solution
4.
Reaction between Sodium sulphate and Barium chloride solutions.
14. a)
To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions.
i)
ZnSO4 (aq.)
ii)
FeSO4 (aq.)
iii)
CuSO4 (aq.)
iv)
Al2 (SO4)3 (aq.)
b)
Arrange Zn, Fe, Cu and Al metals in the decreasing order of reactivity based on
the above result.
15. To study the following properties of acetic acid (ethanoic acid) :
i)
odour
ii)
solubility in water
iii)
effect on litmus
iv)
reaction with sodium bicarbonate
5
Practicals List of Experiments Class-IX
1.
2.
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
ii)
filtration criterion
iii)
stability
To prepare
a)
a mixture
b)
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 as a solvent.
iv)
effect of heat.
3.
To carry out the following chemical reactions and record observations. Also identify
the type of reaction involved in each case.
i)
Iron with copper sulphate solution in water.
ii)
Burning of Magnesium in air.
iii)
Zinc with dilute sulphuric acid
iv)
Heating of Lead Nitrate
v)
Sodium sulphate with Barium chloride in the form of their solutions in water.
4.
To verify laws of reflection of sound.
5.
To determine the density of 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
i)
tap water
ii)
strongly salty water, with the weight of water displaced by it by taking at least
two different solids.
6
7.
To measure the temperature of hot water as it cools and plot a temperature-time
graph.
8.
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 labeled diagrams.
10. To identify parenchyma and sclerenchyma tissues in plants, striped muscle fibers
and nerve cells in animals, from prepared slides and to draw their labeled 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 (b) the presence of the
adulterant metanil yellow in dal.
14. To study the characteristic of spirogyra/Agaricus, Moss/Fern, Pinus (either with male
or female conre) and an Angiospermic plant. Draw and give two identifying features
of groups they belong to.
15. To observe and draw the given specimens-earthworm, cockroach, bony fish and bird.
For each specimen record.
(a)
one specific feature of its phylum.
(b)
one adaptive feature with reference to its habitat.
7
List of Equipments / Materials used in Laboratory
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
Compound Microscope
Dissecting Microscope
Hand Lens
Forceps
Scissors
Scalpel
Needle
Slides
Coverslips
Beaker
Measuring Cylinders
Test Tubes
Boiling Tubes
Spirit Lamp or Burner
Physical balance/Chemical balance
Weight Box
Crucibles
Funnel
Meter Scale
Nails
String or Card
Filter Paper
Whatman's Filter Paper
Conical Flask
Pipettes
Burette
Brush
Petri-dish
Watch Glass
Dropper
Cork
Delivery Tubes
33. Clips
34.
Chromatography Paper
35.
Glass rods
36.
Cork borer
37.
Test Tube Stand
38.
Wire Gauge
39.
Tripod Stand
40.
Stands (Iron/Wooden)
41.
Thermometer
42.
Water bath
43.
Staining Racks
44.
Test Tube holder
45.
Magnets
46.
Spherical Mirrors
47.
Spherical Lenses
48.
Ammeter
49.
Voltmeter
50.
Connecting Wires
51.
Battery
52.
Resitances
53.
Prism
54.
Glass Slab
55.
Alpins
56.
Drawing Board
57.
Drawing Pins
58.
Key
59.
Rheostat
60.
Overflow Can
61.
Slinky
62.
Spring balance
63. Permanent Slide of Binary fission in
Amoeba on Budding in yeast
64.
8
Specimens
List of Chemicals
1.
Safranine Stain
25. Fehling Solution 'B'
2.
Methylene Blue
26. Sodium Chloride
3.
Glycerine
27. Potassium Chloride
4.
Dilute Sulphuric Acid
28. Cobalt Chloride
5.
Potassium Permanganate
29. lodine Solution
6.
Ammonium Oxalate
30. Sudan III
7.
Sucrose
31. Potassium Hydroxide
8.
Boric Acid
32. Potassium Iodide
9.
Magnesium Sulphate
33. Starch
10. Potassium Nitrate
34. Sucrose
11.
35. Ph Paper/Tablets
Acetocarmine Stain
12. Acetic Acid
36. Ketone Bodies
13. Nitric Acid
37. Robert's Solution
14. Hydrochloric Acid
38. Sulphosalicylic Acid
15. Etnanol
39. Biuret reagens
16. Methanol
40. Litmus Solution /Paper
17. Benedict's Reagent
41. Potassium Dichromate
18. Sodium Hydroxide
42. Metal Strips
19. Sodium Carbonate
43. Sodium Hydrogen Carbonate
20. Distilled Water
44. Quick Lime
21. Acetone
45. Aluminium Sulphate
22. Petroleum ether
46. Copper Sulphate
23. Million's Reagent
47. Ferrous Sulphate
24. Fehling Solution 'A'
48. Zinc Sulphate
9
Methodology of Changed
Chemistry Practical IX
Aim :To Carry out the following Chemical reactions and record observations. Also identify
the type of reactions involved in each case.
(A)
(a)
Iron with Copper sulphate solution in water.
(b)
Burning of Magnesium ribbon in air.
(c)
Zinc with dil Sulphuric Acid.
(d)
Heating of head nitrate.
(e)
Sodium Sulphate with barium chloride in the form of their solution in water.
To study the Chemical reaction of Iron with Copper sulphate solution in water and to
identity the type of this reaction.
Apparatus and Chemicals required :Copper sulphate, two iron nails, Test tubes, Thread, distilled water, Stand, sand Paper,
beaker.
Principles :(i)
Solution of Copper sulphate in water is blue in colour.
(ii)
Iron nail is greyish black in colour.
(iii) Solution of ferrous sulphate is light green is colour.
(iv)
Copper metal is a reddish brown or pinkish red metal.
(v) In the activity series iron is lying above the copper, that is iron is more reactive
than copper
(vi)
Iron displaces copper from copper sulphate solution.
CuSO4 + Fe → FeSO4 + Cu.
Fe - 2e- → Fe2+ (oxidized)
Cu2+ + 2e- → Cu (reduced)
(vii) The reaction is a simple displacement reaction.
10
Methods and Procedure :Experiment
Observation
Inference
(a) 1 Dissolve 2g of Copper
Sulphate in 20 mL of
Water, immerse iron nail
in the solution with thread.
After 15 Minutes, on
Copper is displaced from
removing iron nail from
solution by iron.
solution, a brown coating on
the surface of iron is
observed
(b) Compare the colour of
iron nail and the colour
of the solution after
15 Minutes.
It is observed that the colour Iron is more reactive than
of iron nail becomes brown copper.
where as the colour of solution
turned light greenish.
Results :(i)
The green colour of the solution is due to the presence of ferrous irons, where as the
reddish brown colour of the iron nail is due to the deposition of copper metal. This
experiment shows that iron is more electropositive and reactive than copper.
(ii)
The type of reaction involved is(a)
Single displacement reaction.
(b)
Redox reaction.
Precautions :1.
Iron nail should be thorougly cleaned & it should be free from dust, rust and oil etc.
2.
One iron nail should be kept aside for comparison.
3.
The apparatus must be kept undisturbed.
4.
After completing the experiment brown colour of iron nail should not be touched.
(B) To study the change taking place when Magnesium is burnt in air and to identify the
type of this reaction.
Apparatus and Chemicals required :Magnesium Strip, Sand Paper, a pair of tongs, Match Box, burner, china dish, litmus
solution (red)
Principles :1.
Magnesium is an active metal.
2.
Magnesium Combines with Oxygen of air to form magnesium oxide
2Mg + O2 → 2MgO.
3.
Equation solution of Magnesium oxide is basic in nature as it turns red litmus to blue.
4.
The reaction between magnesium and Oxygen is a combination reaction.
11
Methods and Procedure :Experiment
Observation
1. Clean the Magnesium
It is silvery white
ribbon with Sand Paper
Inference
Magnesium metal is silvery
white.
2. Bring one end of
It burns brilliantly and a white Magnesium Combines with
Magnesium strip in contact Powder is formed
Oxygen to form Magnesium
with flame of burner
Oxide (Mgo)
3. Collect and put small
Red litmus paper turns into
amount of white Powder blue.
in a China dish and bring
a moistened litmus paper
in contact with this Powder
Magnesium Oxide Powder
is basic in nature.
Results :1.
Magnesium burns in air with dazzling white flame to form a white powder of magnesium
Oxide.
2Mg + O2 → 2MgO.
2.
Magnesium Oxide is basic in nature.
3.
The type of reaction involved is direct combination reaction.
Precautions :1.
Magnesium ribbon must be thoroughly Cleaned with sand paper.
2.
Magnesium Strip on burning should be handled with the help of pair of tongs.
3.
The dazzling white flame should not be seen with naked eyes.
4.
White Powder of magnesium oxide should not be touched with hands.
(C) To study the chemical reaction taking place between Zinc and dil sulphuric acid and
to identity the type of this reaction.
Apparatus and Chemicals required :Zinc metal, dil sulphuric acid, red litmus paper, conical flask, sodium hydroxide solution.
Principles :(1)
Zinc is an active metal.
(2)
In the activity series of metals, Zinc lies above the Hydrogen, therefore, it displaces
hydrogen from the acids and water.
(3)
The reaction between zinc and dil sulphuric acid is a single displacement reaction,
the hydrogen gas is evolved.
Zn + H2SO4 → ZnSo4 + H2↑
(4)
The addition of Zinc to Sulphuric acid is also a redox reaction.
12
Methods and Procedure :Experiment
Observation
1. Take 2mL of dil sulphuric Formation of bubble takes
acid in a conical flask
place.
and add some Zinc
pieces to it.
Inference
Hydrogen gas is produced
when Zinc reacts with
dil sulphuric acid.
2. Bring moist
(a) red litmus paper in
contact with gas evolved
No change in colour
observed
(b) Blue litmus paper like
above
No change again in colour
is seen.
3. Bring lighted match stick Gas burns with the pop
in contact with the gas
sound
evolved.
4. To the part of the solution
in conical flask add
solution of sodium
hydroxide first a little and
then in excess.
Hydrogen gas is neither
acidic nor basic but it is neutral
Hydrogen gas is combustible
A white gelatinous
Zinc ion is present in
precipitate is formed which the solution
then dissolved in excess of
sodium hydroxide solution
Results :1.
The reaction between Zinc and dil sulphuric acid Produces hydrogen.
Zn + H2SO4 → ZnSO4 + H2↑
2.
The type of reaction involved are :
(a)
Single displacement reaction.
(b)
Redox reaction.
Precautions :1.
Apparatus should be clean and dry.
2.
Sulphuric acid handle with care.
3.
The test of hydrogen gas should be done under the supervision of teacher.
4.
Be attentive to observe the formation of precipitate.
13
(D) To study the effect of heat on the given lead Nitrate crystals and to identify the type of
this reaction.
Chemicals and apparatus required :Lead Nitrate Crystals, Hard glass test tube, test tube holder, burner, blue litmus paper,
starch - iodide paper, Delivery tube, Match box, famous sulphate solution (acidified)
Principles :1.
Lead nitrate is a white crystalline solid.
2.
Lead nitrate on heating decomposes with crackling sound.
3.
↑
↑
∆
2Pb (No3)2 
→ 2PbO + 4NO2 + O2
4.
Nitrogen dioxide gas (NO2) is a reddish brown coloured gas, which acidic in nature
and turns moist blue litmus to red.
5.
When NO2 gas is passed through freshly prepared ferrous sulphate solution acidified,
it turns black.
6.
NO2 gas turns starch iodide paper blue black.
7.
Oxygen (O2) relights or rekindles the glowing splinter.
Methods and Procedure :Experiment
Observation
Inference
1. Heat the given Crystals • Lead Nitrate breaks with • The solid is lead nitrate.
of lead Nitrate in a hard
crackling sound.
glass test tube first gently • A reddish brown & irritating • NO2 gas is evolved.
then strongly
gas is produced
• A Yellow solid is left in the • Yellow residue is Lead
Test tube.
Oxide (PbO)
2. Bring moist blue litmus Blue litmus paper burns red. NO2 gas is acidic in nature.
paper in contact with this
gas.
3. Bring starch iodide paper The paper turns dark blue in The gas evolved is NO2.
in contact with gas
Colour.
4. The Evolved gas is
The solution becomes black The gas is NO2.
passed through acidified
solution of ferrous sulphate
5. Bring a burning splinter
in contact with gas.
Glowing splint is rekindled.
Oxygen (O2) gas is evolved.
6. A solid residue is left
behind.
It is a Yellow solid
The solid is lead oxide (Pbo)
14
Results :On heating lead nitrate, nitrogen dioxide and Oxygen are evolved, a residue of Lead
Oxide is left behind.
2Pb(NO3)2
2PbO + 4NO2↑ + O2↑
The type of reaction involved is Thermal decomposition reaction.
Precautions :1.
2.
3.
4.
Test tube should be clean and dry.
Use test tube holder while heating the test tube.
Mouth of the test tube should be away from the face while heating.
Not to inhale the NO2 gas.
(E)
To study the reaction between aqueous solutions of sodium sulphate and barium
chloride and to identify the type of this reaction.
Chemicals and apparatus required :Barium sulphate solution, sodium sulphate solution, two test tubes, conical flask, glass rod.
Principles :1.
Both the barium chloride and sodium sulphate are soluble in water.
2.
On mixing both the solutions, a double displacement reaction takes place, a white
precipitate of barium sulphate is formed.
Na2 SO4 + Bacl2 → BaSO4↓ + 2Nacl
White ppt.
Method and Procedure :Experiment
1. Mix 10 mL of both the
solution of sodium
sulphate and barium
chloride made in water.
2. Stir the mixture (white
precipitate) with the help
of glass rod.
∆

→
Observation
Inference
A white precipitate is
observed.
White precipitate is
barium sulphate
The white precipitate does White precipitate of
not dissolve on stirring &
barium sulphate is
settles in bottom on standing. insoluble in water.
Results:1.
On mixing barium chloride solution with sodium sulphate, a white precipitate of barium
sulphate is appears.
Bacl2 + Na2SO4 → BaSO4↓ + 2Nacl
2.
The type of reaction involved is :Double displacement reaction (Precipitation)
Precautions:1.
The flask should be clean & dry.
2.
Bacl2 and Na2SO4 should always be in the form of aqueous solutions.
3.
Use small quantity of chemicals.
15
METHODOLOGY OF CHANGED SCIENCE PRACTICAL
(BIOLOGY)
CLASS - IX
Aim :To test
(a)
the presence of starch in a given food sample and
(b)
the presence of adulterant metanil yellow in dal.
(A)
to test the presence of starch in a given food sample.
Materials Required :Test tube, Food sample (water extract from boiled rice or boiled potato), Iodine
Solution, Beaker, Test Tube Stand, Dropper
Basic Principles Involved :Starch forms a dark blue-black colour with Iodine.
Starch (food extract) + Iodine → Blue-Black colour
Procedure : 1.
Boil some rice or potato in a beaker and take the fluid from this beaker as sample for
the experiment.
2.
Put the given sample (about 2mL) in a test tube with the dropper.
3.
Put one or two drops of Iodine Solution into it and mix well.
4.
Observe the change in colour.
Observations :2mL of given sample + 1 or 2 drops of Iodine Solution → Blur - Black Colour
Results : Blue black colour shows the presence of starch in given food sample.
Precautions : 1.
Use clean test tube.
2.
Put the quantity of chemicals as mentioned.
3.
Clean the test tube with water and keep it back on the test tube stand after use.
4.
Don't spill the chemicals / solutions.
16
5.
Use separate dropper for each chemicals.
6.
Don't taste any of the chemicals.
(B) To test the presence of adulterant metanil yellow in dal.
Materials Required : Sample of dal, Test tube stand, concentrated HCl, Test tubes, Beakers, Droppers,
Distilled Water, Test tube holder.
Procedure : 1.
Soak the sample dal in a beaker by adding distilled water into it.
2.
Pour out the liquid to another beaker which can be used as a sample.
3.
Put 2mL of this sample into a clean test tube by using a dropper.
4.
Add 2-4 drops of Conc. HCl in the test tube.
5.
Observe the changes.
Observations :2mL of sample dal + 2-4 drops of conc. HCl → A pink or magenta colour appears
Result :The given sample of dal contains metanil yellow.
Precautions : 1.
Use clean test tube.
2.
Add the quantities of chemicals / solutions as mentioned.
3.
Hold the test tube with a test tube holder while adding conc. HCl.
4.
Handle conc. HCl bottle very carefully.
5.
Do not allow to spill conc. HCl on your body or on your clothes.
6.
Use separate dropper for each chemical.
17
METHODOLOGY OF CHANGED CHEMISTRY PRACTICAL
CLASS - X
Aim :(A)
To perform and observe the following reactions.
(a)
Action of water on quick time.
(b)
Action of heat on ferrous sulphate.
(c)
Iron nail kept in copper sulphate solution.
(d)
Reaction between sodium sulphate and barium chloride solutions.
(B) Classify the above reactions into
(A)
(a)
Combination reaction
(b)
Decomposition reaction
(c)
Displacement reaction
(d)
Double displacement reaction
To perform and observe the action of water on quick lime and classify the type of this
reaction.
Apparatus and chemicals required :Quick lime (calcium oxide), distilled water, Beakers, Test tubes, filtration set, red litmus
paper.
Principles :•
When quick lime is added in water, the following reaction occurs:
CaO + H2O → Ca(OH)2 + Heat
quick lime
slaked lime
•
In this reaction two substances are combined to form a new substance. Therefore, it
is called combination reaction.
•
The heat is evolve during the reaction, so called exothermic reaction also.
•
Slaked lime is basic in nature, it turns red litmus to blue.
18
Method and Procedure :Experiment
Observation
Inference
1. 40mL water in a beaker Brisk reaction begins
& add 4g of quick lime
to it. Stir it with clean
glass rod.
A new substance is
formed.
2. Touch outer surface of
the beaker.
Its outer surface is hot.
Heat is evolved due to the
the action of water on quick
lime.
3. Place a drop of liquid
with the help of dropper
on a red litmus paper.
It turns blue.
New substance formed is
basic in nature.
4. Take about 10mL filtered Clear filtrate turns milky
liquid from the above
on passing CO2 through it.
beaker and blow air
from your mouth.
The new substance
formed. i.e. slaked lime.
Results : 1.
Water and quick lime (calcium oxide) directly combine to form calcium hydroxide (a
single new substance).
2.
∆ as the single new substance is formed.
The reaction is called combination reaction,

→
3.
A large amount of heat is evolved during the reaction, so called exothermic reaction.
CaO + H2O → Ca(OH)2 + Heat
Precautions : 1.
Quick lime should not be touched with hands.
2.
Add quick lime into water very carefully to avoid spurting of the mixture.
3.
CO2 should pass in clear slaked lime solution only for a short time.
(B) To perform and observe the action of heat on ferrous sulphate crystal and to identify
this type of reaction.
Chemical and apparatus required : Solid ferrous sulphate crystals, test tubes, test tube holder, blue litmus paper, acidified
solution of potassium dichromate.
Principles :•
On heating Ferrous sulphate crystals, the following reaction occurs :2FeSO4
Fe2O3 + SO2↑ + SO3↑
19
•
In this reaction a single substance breaks into simpler ones, so called decomposition
reaction.
•
SO2 & SO3 turns blue litmus to red & are acidic in nature.
•
SO2 turns orange colour of acidified potassium dichromate solution to green, so it
has reducing property.
Method and Procedure :Experiment
Observation
Inference
1. Take 2g of solid ferrous
sulphate in a clear and
dry test tube, heat it
gently over a flame of
burner.
A colourless gas is formed
and brown yellow solid is
left in the test tube.
Ferrous sulphate
decomposes on heating.
2. Smell the gas evolved
carefully.
It smells like burning sulphur.
The gases are oxides of
sulphur.
3. Bring a moist blue litmus Blue litmus paper turns to red.
paper near the mouth of
test tube.
Oxides of sulphur are
acidic in nature.
4. Bring a paper strip
soaked in acidified
potassium dichromate
solution over the mouth
of test tube.
Sulphur di oxide has
reducing property.
The orange colour of paper
strip turns to green.
Results :•
When ferrous sulphate heated, it decomposes into ferric oxide and oxides of sulphur.
2FeSO4 Fe2O3 + SO2↑ + SO3↑
•
The gas evolved is a mixture of SO2 + SO3 which reduces the solution of potassium
dichromate.
K2Cr2O7 + H2SO4 + 3SO2 → Cr2 (SO4)3 + K2SO4 + H20
Orange
•
Green
The type of reaction involved is thermal decomposition reaction.
Precautions : 1.
The test tube should be well cleaned and dry.
2.
Inhalation of produced gas should be avoided.
3.
Potassium di chromate solution should be acidified by adding few drops of dil. sulphuric
acid.
20
(C) To perform and observe the reaction between iron nail and copper sulphate solution
and to identify the type of this reaction.
Chemicals and Apparatus required :Iron nails, copper sulphate solution, test tube, thread, stand.
Principles :•
When iron nail is kept in a solution of copper sulphate which is blue in colour, the
following reaction occurs :
Fe
+ CuSO4 → FeSO4
Grey
•
Blue
+
Cu
Light green
Reddish brown
In the reaction the iron has replaced copper from copper sulphate solution, so called
displacement reaction.
Method and Procedure :Experiment
Observation
Inference
1. Add 2g of copper
sulphate in 20mL of
water, dip an iron nail
in the solution with
thread.
After few minutes, a brown Copper is displaced from
coating is observed on iron solution by iron.
nail.
2. Compare the colour of
iron nail and solution
before and after the
experiment performed.
The colour of iron nail become The iron is more reactive
brown where as the solution than copper.
turns to light green.
Results :1.
The green colour of the solution is due to the presence of ferrous ions, where as the
reddish brown colour on iron nail is due to the deposition of copper metal.
2.
This shows that iron is more reactive / electropositive than copper in the activity series
of metals.
3.
The type of reaction involved is single displacement reaction.
Precautions :1.
Iron nail should be well cleaned before dipping in the solution.
2.
The apparatus must keep undisturbed.
(D) To perform and observe the reaction between sodium sulphate and barium chloride
in aqueous solution and to identify this type of reaction.
Chemical and Apparatus required :Solid sodium sulphate, Barium chloride solution, Test tubes, Distilled water, conical flask.
21
Principles :When the solutions of sodium sulphate and barium chloride are mixed together, a
white precipitate of barium sulphate is formed.
Na2SO4 + Bacl2
→ BaSO4
+
2Nacl
White ppt.
In the above reactions there is exchange of ions between two therefore, it is an example
of double displacement reaction.
Method and Procedure :Experiment
Observation
Inference
1. Take 10mL solution of
On mixing the two solutions, White Precipitate is
sodium sulphate in a
a white precipitate is
barium sulphate.
test tube and 10mL of
observed immediately.
barium chloride solution
in an other test tube, mix
together in a flask.
2. The above mixture is
left undisturbed for
some time.
White ppt. is settles down in White ppt. of barium
the bottom and transparent sulphate is insoluble in
liquid is observed above it. water.
Result :1.
On mixing the solutions of barium chloride and sodium sulphate, a white precipitate
of barium sulphate is formed.
Bacl2 +
Na2SO4 →
BaSO4 + 2Nacl
White ppt.
2.
In the reaction the exchange of ions takes place, so the type of reaction is double
displacement reaction.
Precautions :1.
The solutions should be prepared in distilled water.
2.
The flask should be clean and dry.
3.
Use the chemicals in small quantity.
22
General and specific duties of the laboratory assistants of the schools of Delhi
Administration have been assigned by the Science branch. These are highly
required for the upkeep of the laboratory, smooth conduct of the practical work
and for the attainment of the higher level of learning.
iz;ksx'kkyk lgk;d dh M~;wVht & iz;ksx'kkyk lgk;d ds iz;ksx'kkyk lEcU/kh rFkk vU; D;k&D;k
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tkudkjh pkfy;s rks og Hkh tkuukA
8-
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lgk;d dks izkFkfed fpfdRlk dk Kku gksukA
23
13- os lHkh foKku lac/a kh dk;Z djuk ftUgsa iz/kkukpk;Z ;k f'k{kk vf/kdkjh mi;qDr le>sAa
HkkSfrd %
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24
Some Guidelines For Lab Assistants
A lab assistant is the manger who is incharge of the stockroom and laboratory
preparation. She/He should present him/her self in a professional image and thus should
follow some guidelines in this context.
-
They are expected to be clean & well groomed.
-
During the period in which the students are working, they should move around the
room to insure that the students are carrying out instructions in a safe and correct
manner.
-
They should watch for minor safety or contamination information such as leaving
reagent bottles open, pouring or inserting material in reagent bottles, lighting burner
near flammable reagents etc.
-
They should maintain the laboratory, in view of clearing of glass panes, polishing of
tables, almirah and general cleanliness.
-
Maintenance of equipment of lab repairs and cleaning.
-
Recognition, classification and use of science apparatus.
-
Arrangement of stock in almirah and laboratory.
-
Improvising the apparatus from junk and common material.
-
Use of common work and tools.
-
First aid in case of accident in the laboratory.
-
Recognizes the different plants and their preservation, maintenance of biology museum
and aquarium etc.
-
Beyond all he/she should be a cultured person & behave themselves in decent manner.
-
They should have an ability to control their emotions.
-
They should be disciplined, honest and punctual.
-
They should take an initiative in all activities in laboratory.
Some Do's-
Become familiar with the experiments being performed.
-
Check to be sure the correct lab drawers are unlocked prior to lab.
-
Know where all safety equipment are in lab.
-
Maintain the register having a record of practicals and articles/items issued to the
students.
25
-
Helps the students to maintain to clean and safe laboratory environment.
-
Insure that the students replace, reagents back in proper place.
-
Be prepared and aware of safety procedure for emergency or injury situations.
-
Report damaged equipment and replace broken glassware.
Some Don'ts -
Make personal, prolonged telephone calls.
-
Sit in one place and do nothing or talk.
-
Make measurements or carry out any laboratory procedure for the students.
-
Be rude, abusive or overbearing to students.
-
Socialize with the students.
26
Acknowledgment
The Coordinator Dr. S.V. Malik SCERT is grateful to the members of the supplementary
booklet of Laboratory manual development team. The names of the participating members
of the manual -
Advisors
Mr. Ravinder Kumar
Principal
SCSD Sec IX, Rohini Delhi
Sh. R. M. Mohla
Coordinator teacher's training
UEE Mission
1.
Mr. Ravinder Kumar
-
Principal
SCSDSV Sec IX, Rohini Delhi
2.
Mr. Ashok Anand
-
Vice Principal
GBSS Shahbad Diary, Delhi
3.
Mr. Lalit Gupta
-
TGT (Natural Science)
GBSSS Hastsal, New Delhi
4.
Mr. V.S. Malik
-
Lecturer Biology
RPVV Civil Lines, Delhi
5.
Ms. Sangeeta Ohri
-
TGT (Natural Science)
SCSD SV Sec IX, Rohini Delhi
27