Why does not ZnS get precipitated when `H_2S` is passed through an acidic solution of Zn -salt?

Both Cus and ZnS are precipitated if H_(2)S gas is passed through an alkaline solution of Cu^(2+) and Zn^(2+) . Explain.

In qualitative analysis, a black precipitate is obtained when H_(2)S is passed through an acidified aqueous solution of a salt . A blue coloured solution is obtained on boiling the preciptate with dilute HNO_(3) . The substance obtained on addition of excess of ammonia solution to this blue solution is -

Write down the formula of the black precipitate formed when H_2S gas is passed through an aqueous solution of lead nitrate?

Why does the path of light become visible when passed through a colloidal solution?

What happens when Cl_2 gas is passed through cold lime solution. What is table salt?

What change of colour is observed when H_2S gas is passed through an acidified aqueous solution of potassium dichromate?

What happens when sulphur dioxide is passed through an aqueous solution of Fe (III) salt?

What is the coordination entity formed when excess of aqueous KCN is added to aqueous solution of CuSO_(4) ? Why is it that no precipitate of copper sulphide is obtained when H_(2)S(g) is passed through this solution ?

When H_(2)S is passed through Hg_(2)^(2+) , we get :