Question

What do you observe when ammonia solution is added dropwise and then in excess to FeCl3 reaction ?

Answer 1

On adding little ammonia solution on copper sulphate solution, we get a pale blue precipitate of copper hydroxide. Now when we add excess ammonia solution, the precipitate dissolves, forming a deep azure blue solution. The above complex salt is called copper tetrammene sulphate, which is a deep blue solution.