Aim: To study the reactions of the metals Zn, Fe, Cu and Al with the solutions of salts ZnSO,
FeSO,, CuSo, Al2(S0,), and to arrange these metals in the decreasing order of their
reactivity.
Apparatus : Test tubes, test tube stand, distilled water, sand paper, etc.
Chemicals : The metals Zn, Fe, Cu and Al; solutions of the salts ZnSO,, FeSO,, CuSO,, Al2(SO2),
Figure : (Draw figure)
Answers
Explanation:
Aim
To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions:
ZnSO4 (aq), FeSO4 (aq), CuSO4 (aq), Al2(SO4)3 (aq)
To arrange Zn, Fe, Cu and Al metals in the decreasing order of reactivity based on the above results.
Materials Required
Aluminium foil, copper turnings, zinc granules, iron filings, ferrous sulphate solution, copper sulphate solution, zinc sulphate solution, aluminium sulphate solution, test tubes, test tube stand and four beakers of 50 ml.
Theory
Different metals have different reactivities towards chemical reagents. Some metals are more reactive than others. The metals, which can lose electron more readily to form positive ions are more reactive.
According to the reactivity series (or activity series) of metals, a more reactive metal displaces a less reactive metal from its aqueous salt solution. These reactions are called displacement reactions.
Displacement reactions can be used to find out the relative reactivities of metals.
Example If a piece of zinc metal is dipped in a solution of copper sulphate, zinc will displace copper from copper sulphate. The blue colour of copper sulphate solution will gradually fade and finally colourless solution of zinc sulphate will be obtained.
CBSE Class 10 Science Lab Manual – Reactivity Series 1
It means that zinc has displaced copper from copper sulphate solution, i.e. zinc is more reactive than copper.
Al can displace Zn, Fe, Cu from their salt solutions, therefore it is more reactive than Zn, Fe and Cu.
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)
Zn can displace Fe and Cu from their salt solutions, therefore zinc is more reactive than Fe and Cu.
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
Fe can displace copper from copper sulphate solution, therefore it is more reactive than copper.
Fe(s) + CuSO4(aq) ——–> FeSO4(aq) + Cu(s)
Fe(s) + ZnSO4 (aq) ——–> No reaction
Fe(s) + FeSO4(aq) ——–> No reaction
Fe(s) + Al2(SO4)3(aq) ——–> No reaction
Cu cannot displace any of the given metals from their salt solutions, therefore it is least reactive than the other given metals.
No reaction takes place when any of the metals copper, iron, zinc and aluminium are placed in aqueous aluminium sulphate solution. From this, it can be concluded that aluminium is the most reactive and copper is the least reactive among the given four metals (Fe,Zn,Cuand Al). Thus, the decreasing order of reactivity of metals is
Al > Zn > Fe > Cu
Metals and their aqueous salt solutions exhibit colours as follows:
S. No. Name and formula Colour
1. Zinc sulphate (ZnS04) Colourless
2. Ferrous sulphate (FeS04) Light green
3. Copper sulphate (CuS04) Blue
4. Aluminium sulphate AI2(S04)3 Colourless
5. Aluminium (Al) White
6. Iron (Fe) Blackish grey
7. Copper (Cu) Reddish brown
8. Zinc (Zn) Silvery white (greyish)
Procedure
Prepare 50 ml solutions of 5% concentration (by volume) of zinc sulphate, iron(II) sulphate, copper(II) sulphate and aluminium sulphate in distilled water in four different beakers. Label these beakers as P, Q, R and S (as shown in Fig.1).
CBSE Class 10 Science Lab Manual – Reactivity Series 2
Take about 10 mL of saturated solution of zinc sulphate (ZnSO4), ferrous sulphate (FeSO4), copper sulphate (CuSO4) and aluminium sulphate [Al2(SO4)3] in the respective test tubes (as shown in Fig. 2). Observe the colour of the solutions.
CBSE Class 10 Science Lab Manual – Reactivity Series 3
Take zinc, copper, iron and aluminium metal strips and clean their surfaces.
Put zinc metal strip in all the four test tubes A, B, C and D and observe the change that follows.
Repeat the above experiment with other metal strips by dipping them in fresh salt solutions of metal and observe for displacement reactions.
Observation Table