Which of the following will be more soluble in an acidic solution than in pure water?

Question

AgI, Ni(OH)2, KClO4, SrSO4, CaCO3

Answer 1

The secret to these is knowing what anions react with H^+ (the acid) and if any weak acids or precipitates are formed.

For AgI the acid would be HI and that is a strong acid; therefore, AgI is NOT more soluble in acid than in water.

For Ni(OH)2, adding H^+ reacts with OH to form H2O so YES, it is more soluble in acid than in H2O

For KClO4, adding H^+ forms HClO4 but that is a strong acid so it is NOT more soluble in acid.

SrSO4 would be HSO4^- and that is k2 for H2SO4 so YES.

CaCO3 would be HCO3^- which is k2 for H2CO3 and YES.

Answer 2

Ni(OH)2