Вопрос № 1. Properties of amphoteric hydroxides, acids and salts.

A solution of copper sulfate (II) was placed in two test tubes. A solution of a substance 1 was added to the first tube which led to the formation of a precipitate and release of gas.. A solution of a substance 2 was added to the second tube which led to the formation of a blue precipitate. Of the following substances, deside which substances are 1 and 2.