Addition of $SnCl_2$ to $HgCl_2$ gives a precipitate of which color?

Identify the metal $M$ and the precipitate $Z$ in the following reaction sequence:
$MSO_4$ $\xrightarrow{NH_4OH} \downarrow X \text{ (white)}$ $\xrightarrow{NH_4OH \text{ (excess)}} Y$ $\xrightarrow{H_2S} \downarrow Z$

$A$ metal salt gives a yellow precipitate with potassium chromate in acetic acid and a white precipitate with dilute sulfuric acid,but it does not give a precipitate with sodium chloride or sodium iodide. What will be the composition of the white precipitate formed when sodium carbonate is added to the solution of this metal salt?

The solution of $BiCl_{3}$ in dil. $HCl$ when diluted with water,forms a white precipitate which is:

Which ion$(s)$ precipitate when an oxalate solution is added to a mixture of $Ba^{2+}$,$Sr^{2+}$,and $Ca^{2+}$?

$A$ colorless aqueous solution contains nitrates of two metals,$X$ and $Y$. When it was added to an aqueous solution of $NaCl$,a white precipitate was formed. This precipitate was found to be partly soluble in hot water to give a residue $P$ and a solution $Q$. The residue $P$ was soluble in aqueous $NH_3$ and also in excess sodium thiosulfate. The hot solution $Q$ gave a yellow precipitate with $KI$. The metals $X$ and $Y$,respectively,are