(a) zinc is more electropositive than compared to copper therefore when
zinc strip is dipped into copper sulphate solution it displaces copper
from its solution and form zinc sulphate solution. it can also be writen as because zinc metal is more teactive than copper therfore it displayes coppe from its solution.
CuSO4 + Zn ( 0) ------- ZnSO4 + Cu(0)
(b) Al+HCl gives AlCl3+hydrogen So aluminium chloride is formed as a result.
(c) If silver METAL (Ag0) is added to a solution of CuSO4, nothing happens
since silver is already reduced and it wants to stay that way..............