Find· the number of reagent(s) which form white ppt. with ${\mathrm{CO}}_3^{2-}$ion.

${\mathrm{BaCl}}_2,{\mathrm{CuSO}}_4,{\mathrm{HgCl}}_2,\mathrm{Pb}{\left({\mathrm{CH}}_3\mathrm{COO}\right)}_2,{\mathrm{CaCl}}_2$

The number of reagent(s) which form white ppt. with ${\mathrm{CO}}_3^{2-}$ion

${\mathrm{BaCl}}_2,{\mathrm{HgCl}}_2$ and  ${\mathrm{CaCl}}_2$ .

Thus, the correct answer is 3.