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?

(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.