When ferrous sulphate is added to mercuric chloride then

What happens when : (i) Ferric chloride is added to potassium ferrocyanid. (ii) Iron reacts with cold dilute nitric acid. (iii) Potassium ferricyanide is added to ferrous sulphate. (iv) Excess of potassium iodide is added to mercuric chloride. (v) Silver chloride is treated with aq. sodium cyanide and the product thus formed is allowed to react with zinc in alkaline medium.

What happens when phosphine is absorbed in mercuric chloride solution ?

What happens when phosphine is absorbed in mercuric chloride solution ?