Question

Why is CuCl formed from the corrosion reaction of Cu(s) and HCl?

Answer 1

Because the copper displaces the hydrogen in the acid, forming the copper chloride salt.

Explanation:

Cu(s) and HCl(aq) do not react under normal S.T.P conditions, as copper is below in the reactivity series (less reduction potential) and thus cannot displace hydrogen in the acid to form copper chloride. However, in the presence of pure `O_2`, it follows the following equation:

`Cu_((s))+2HCl_((aq))+1/2O_(2) -> CuCl_(2)(aq) + H_(2)O(l)`

So, copper reacts with the hydrochloric acid, replacing the hydrogen and taking it's place in the acid, forming the copper chloride salt along with water. So, this is why copper chloride is formed in the corrosion and single displacement reaction of solid copper and hydrochloric acid.