Q3.
Ms Nisha, a science teacher set up the given apparatus to demonstrate displacement reactions:
Cuso,
solution
ZnSO
solution
Feso,
solution
Cuso,
solution
Fe
Fe
filings
Cu
filings
filings
Zn
filings
(IV)
(11)
Which of the following statements is correct?
A)
B)
Copper will be precipitated in beaker I and there will be no change in beakers. II, III and IV.
Copper will be precipitated in beaker IV and solutions in beakers I, II and III will become
colourless.
C There will no change in beakers II and III and solutions in beakers I and IV will turn green
and colourless respectively.
D) There will be no change in beakers II and III and solutions in beakers I and IV will become
colourless and green respectively.
Answers
Answer:
In this article, we have discussed a step by step procedure to perform CBSE Class 10 Science Practicals experiment Reactivity Series. It will help you understand the reaction of metals such as zinc, aluminium, copper, and iron with aqueous salt solutions of aluminium sulphate, copper sulphate, ferrous sulphate, and zinc sulphate. Also, after performing the experiment Reactivity Series of Metals, you will be able to analyse the decreasing order their reactivity.
Aim:
Observing the action of zinc, iron, copper and aluminium metals for the following salt solutions.
Zinc sulphate (ZnSO4)
Copper sulphate (CuSO4)
Ferrous sulphate (FeSO4)
Aluminium sulphate (Al2(SO4)3)
Arranging the metals Zinc, Copper, Iron, and Aluminium in the decreasing order of reactivity based on the results obtained from the above.
Materials required:
Aluminium foil
Zinc granules
Copper turnings
Iron filings
Copper sulphate solution
Aluminium sulphate solution
Zinc sulphate solution
Four 50ml beakers
Test tube
Test tube stand
Theory:
What is reactivity series?
Different metals have different reactivities with chemical reagents. The metals that form positive ions by losing electrons more readily. A more reactive metal displaces a less reactive metal from salt solution. Such reactions are called displacement reactions. Consider an example, if a small amount of zinc is dipped in copper sulphate solution, zinc is displaced from copper sulphate. The blue colour of copper sulphate fades and colourless zinc sulphate solution is obtained. Therefore zinc is more reactive than copper.
Aluminium has the ability to displace zinc, iron, copper from their respective salt solutions and therefore is more reactive than them.
Reactions:
2Al(s) + 3ZnSO4(aq) –→ Al2(SO4)3 3Zn(s)
2Al(s) + 3FeSO4(aq) –→ Al2(SO4)3 3Fe(s)
2Al(s) + 3CuSO4(aq) –→ Al2(SO4)3 3Cu(s)
Zinc has the ability to displace iron, copper from their respective salt solutions and therefore is more reactive than them.
Reactions:
Zn(s) + CuSO4(aq) –→ ZnSO4 (aq) + Cu(s)
Zn(s) + FeSO4(aq) –→ ZnSO4 (aq) + Fe(s)
Zn(s) + Al2(SO4)3(aq) –→ no reaction
Zn(s) + ZnSO4(aq) –→ no reaction
Iron has the ability to displace copper from its salt solution and therefore is more reactive when compared to Cu.
Reactions:
Fe(s) + CuSO4(aq) –→ FeSO4 (aq) + Cu(s)
Fe(s) + FeSO4(aq) –→ no reaction
Fe(s) + Al2(SO4)3(aq) –→ no reaction
Fe(s) + ZnSO4(aq) –→ no reaction
No reaction occurs when any of the metals from zinc, iron, aluminium, and copper are placed in aqueous solution of Al2(SO4)3.
Therefore from the above, we can conclude the reactivity of elements in the following order –
Aluminium is more reactive than Zinc.
Zinc is more reactive than Fe.
Fe is more reactive than Cu.
Hence Aluminium is the most reactive and Copper being the least reactive metal.
The below table gives you an understanding of the colours exhibited by the metals and their salts:
Compound nameFormulaColourAluminium sulphateAl2(SO4)3ColourlessCopper sulphateCuSO4BlueZinc sulphateZnSO4ColourlessFerrous sulphateFeSO4Light greenCopperCuReddish brownAluminiumAlWhiteZincZnSilver whiteIronFeBlackish grey
Experimental Setup:


Procedure:
Wash four beakers with distilled water, dry them and label them A, B, C, D.
Prepare 50 mL solution with 5% concentration by volume of ferrous sulphate, aluminium sulphate, copper sulphate, zinc sulphate.
Pour ZnSO4 in beaker A, FeSO4 in beaker B, CuSO4 in beaker C, Add Al2(SO4)3 in beaker D.
Wash four test tubes with distilled water and dry them.
Put them in a test tube stand and label them as P, Q, R, and S as shown in the figure above.
Take 10 mL of the saturated ferrous sulphate (FeSO4), copper sulphate (CuSO4), zinc sulphate (ZnSO4), and aluminium sulphate (Al2(SO4)3 ) in