Question

Samples of four metals A, B, C and D were added one by one to the following solutions. The results obtained were tabulated as follows:

Solution →	Iron Sulphate	Copper Sulphate	Zinc Sulphate	Aluminium Sulphate
Metal ↓
A	-	Displacement	No reaction	No reaction
B	Displacement	Displacement	Displacement	-
C	Displacement	?	-	No reaction
D	No reaction	No reaction	No reaction	No reaction

Use the table above to answer the following questions about metals A, B, C and D:

1. Which is the least reactive metal?
2. What would be observed if C is added to a solution of copper sulphate?
3. Arrange the metals A, B, C and D in the order of their decreasing reactivity.

Answer 1

1. Since it doesn't react with either solution, "D" is the least reactive metal.
2. Zinc sulphate would make a white solution. More zinc than copper would cause a blue solution to turn white. Therefore, ‘C’ might be zinc.
3. Reactivity of metals would be B > C > A > D. D is more reactive than iron because it exhibits no reaction with any solution, but A can only displace copper sulphate, while ‘C’ can displace both copper sulphate and iron sulphate. All of the salt’s metals can be replaced with Metal B, which is the most reactive.