Chemistry
Samples of four metals A, B, C and D are taken and were added to the following solutions one by one. The results obtained have been tabulated as follows :
Solution to which metal is added
| Metal | Iron (II) sulphate | Copper (II) sulphate | Zinc sulphate | Silver nitrate |
|---|---|---|---|---|
| A | No reaction | Displacement | ----- | ----- |
| B | Displacement | ----- | No reaction | ----- |
| C | No reaction | No reaction | No reaction | Displacement |
| D | No reaction | No reaction | No reaction | No reaction |
Use the table given above to answer the following questions:
(a) Which is the most reactive metal ?
(b) What would you observe when B is added to solution of copper (II) sulphate ?
(c) Arrange the metals A, B, C and D in order of increasing reactivity.
Answer
(a) B is the most reactive metal.
Reason — B displaces iron from iron (II) sulphate solution, showing that B is more reactive than iron. It does not displace zinc from zinc sulphate solution, so it is less reactive than zinc. Among the given metals A, B, C and D, metal B is the most reactive.
(b) The blue colour of copper (II) sulphate solution will fade, and a reddish-brown deposit of copper will be formed.
Reason — Since B is more reactive than iron, it is also more reactive than copper. Hence, it will displace copper from copper (II) sulphate solution.
(c) D < C < A < B
Reason — A metal displaces another metal from its salt solution only if it is more reactive than that metal.
- B displaces iron from iron (II) sulphate, so B is more reactive than iron.
- A displaces copper from copper (II) sulphate but does not displace iron from iron (II) sulphate, so A is less reactive than B.
- C displaces silver from silver nitrate but does not displace copper from copper (II) sulphate, so C is less reactive than A.
- D does not displace silver from silver nitrate, so D is the least reactive.
Hence, the increasing order of reactivity is:
D < C < A < B
Related Questions
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(a) What is a decomposition reaction ?
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(b) Give a balanced equation for this reaction.
(c) Give three applications of neutralization reactions.
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