(i) Blue colour of copper sulphate solution gets disappears.
Reason Aluminium reacts with dilute hydrochloric acid to form aluminium chloride and hydrogen gas.
(ii) Hydrogen gas is evolved.
Reason Zinc reacts with copper sulphate to form colourless zinc sulphate solution and solid copper in deposited form.
(iii) No reaction occurs.
Reason Silver metal is less reactive than copper, therefore, it cannot displace copper from copper sulphate solution.