When H2S gas is passed through an acidified solution of CuSO4, a black precipitate is obtained.

Ans.

1. Hydrogen sulphide reacts with an acidified solution of CuSO_4­, to form a black insoluble copper sulphide.
2. Hence, when H₂S gas is passed through an acidified solution of CuSO₄, a black precipitate is obtained.