Question

On adding dilute hydrochloric acid to copper oxide powder, the solution formed is blue-green.
(a) Predict the new compound formed which imparts a blue-green colour to solution.
(b) Write a balanced chemical equation of the reaction which takes place.
(c) On the basis of the above reaction, what can you say about the nature of copper oxide?

Answer 1

(a) When cupric oxide is treated with dilute hydrochloric acid, copper(II)chloride (blue-green salt solution) and water are obtained.

(b) CuO(s) + 2HCl(aq) → CuCl₂(aq) + H₂O(l)

(c) The reaction between a metal oxide and hydrochloric acid is similar to the neutralisation reaction in which, after the reaction, a salt and water are formed. So, we can conclude that copper oxide is basic in nature.