What is formed when calomel $(Hg_2Cl_2)$ reacts with $NH_4OH$?

Compound $X$ is tested and the results are shown in the table.

Test	Result
Aqueous $NaOH$ is added, then heated gently.	Gas given off which turns damp red litmus paper blue.
Dilute $HCl$ is added.	Effervescence, gas given off which turns lime water milky and acidified $K_2Cr_2O_7$ paper green.

Which ions are present in compound $X$?

Sodium carbonate cannot be used in place of ammonium carbonate for the precipitation of the fifth group radicals because

If $Pb^{2+}, Cu^{2+}, Al^{3+}, Cd^{2+}, Zn^{2+}$ radicals are present in an aqueous solution,and it reacts with $H^{+}/H_2S$,a precipitate is produced. The solution $(X)$ obtained after the removal of the precipitate is treated with excess $NaOH$. What is the result?

$A$ salt on treatment with dil. $HCl$ gives a pungent smelling gas and a yellow precipitate. The salt gives a green flame when tested. The salt solution gives a yellow precipitate with potassium chromate. The salt is:

$Pb^{2+}$,$Cu^{2+}$,$Zn^{2+}$,and $Ni^{2+}$ ions are present in a given acidic solution. On passing hydrogen sulphide gas through this solution,the precipitate formed will contain: