Question

On adding dilute HCI to copper oxide powder, the solution formed is blue-green. Predict the new compound formed which imparts a blue-green colour to the solution.

Answer 1

The new compound formed is copper(II) chloride (CuCl₂₎, which imparts blue-green colour to the solution.
 CuO + 2HCl  ------> CuCl₂ +     H₂O

   copper oxide              copper (II)chloride

                                          ( Blue-green )