15. which one of the following compounds is insoluble in water? a) pb(clo4)2 b) mgso4 c) ca(no3)2 d)…

Brief Explanations:

According to solubility rules: Perchlorates ($ClO_4^-$), sulfates ($SO_4^{2 -}$) with some exceptions (like $BaSO_4$, $PbSO_4$ etc.), nitrates ($NO_3^-$) and most acetates ($CH_3COO^-$) are soluble in water. Chlorides ($Cl^-$) are generally soluble, but $Hg_2Cl_2$ is an insoluble chloride.

Answer:

E. $Hg_2Cl_2$