Question

$PbSO_{4}$, $BaSO_{4}$, AgCl, AgBr, AgI are insoluble in water, why?

Answer 1

If the compounds are soluble in water they must be dissociates into ions and solubility of the compound depend upon the lattice energy and hydration energy of a central metal atom.

$The\quad given\quad compounds\quad are\quad Pb{ SO }_{ 4 },\quad Ba{ SO }_{ 4 },\quad AgCl,\quad AgBr\quad or\quad AgI, etc.$

All the given compounds are ionic but these are insoluble in water because of the high value of lattice energy which exceeds the hydration energy of the central metal ion.