During the reaction, sodium sulfide is hydrolyzed to produce a certain amount of H2S, so a small amount of yellowish sulfur precipitate will be produced.

(So? )? + 4H+ + S？ = = So? +S↓+H？ O

It is made by reacting copper sulfate with ammonia water and slowly adding ethanol. The main principles of its compilation are:

CuSO？ +4NH？ +H？ O==[Cu(NH？ )? ] So? h？ O

① Add a small amount of ammonia water to copper sulfate solution: Cu? +2NH？ h？ O==Cu(OH)？ ↓+2NH？

② Excessive ammonia: Cu? +4NH？ h？ O==[Cu(NH？ )? ]? +4H？ O

Extended data

Inorganic chemistry experiment is a course closely coordinated with inorganic chemistry theory course. Experiments enrich the study of theoretical courses with chemical facts, and theoretical courses play the role of explaining chemical phenomena and finally curing experimental results with chemical reaction equations.

For example, there is an experiment in the section "Formation and Properties of Complexes". To1ml1mol l-1cuso? Drop 2 mol L- 1 ammonia water into the solution, and observe the formation of precipitate first. Then, excessive ammonia water was added dropwise to observe the precipitation and dissolution.

In this case, the obtained precipitate is considered to be Cu(OH)? , is obviously wrong. Because, in the theory textbook, we can find the hint that the precipitate is light blue basic copper sulfate.

Baidu Encyclopedia-Tetraammonium Copper Sulfate