An aqueous solution of an inorganic compound $\left(\mathrm{X}\right)$ gives the following reactions:

$\left(\mathrm{i}\right)$ With the aqueous solution of barium chloride, a precipitate insoluble in dilute $\mathrm{HCl}$ is obtained.

$\left(\mathrm{ii}\right)$ The addition of excess $\mathrm{KI}$ gives a brown precipitate, which turns white on the addition of an excess of hypo.

$\left(\mathrm{iii}\right)$ With an aqueous solution of ${\mathrm{K}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$, a chocolate-coloured precipitate is obtained.

Identify the compound $\left(\mathrm{X}\right)$ and give the equations for the reactions $\left(\mathrm{i}\right), \left(\mathrm{ii}\right)$ and $\left(\mathrm{iii}\right)$.

A metal chloride $\left(\mathrm{X}\right)$ shows the following reactions:

(i) When ${\mathrm{H}}_2\mathrm{S}$ is passes in an acidified aqueous solution of $\left(\mathrm{X}\right)$ a black ppt is a obtained.

(ii) The precipitate obtained in step (i) is not soluble in yellow ammonium sulphide.

(iii) When a solution of stannous chloride is added to an aqueous solution of $\left(\mathrm{X}\right)$,a white precipitate is obtained which turns grey on addition of more of stannous chloride.

(iv) When an aqueous solution of $\mathrm{KI}$ is added to an aqueous solution of $\left(\mathrm{X}\right)$, a red precipitate is obtained which dissolves on addition of excess of $\mathrm{KI}$.

Identify $\left(\mathrm{X}\right)$ and write down the equations for the reaction at steps (i), (iii) & (iv).