A white precipitate obtained on adding dilute H2SO4 to a lead salt solution dissolves in hot concentrated ammonium acetate. This is because

weakly ionised lead(II) acetate/acetato complexes form, lowering [Pb^2+] below the K_sp of PbSO4

PbSO4 is converted to the more soluble PbCl2

JEE Main levelSingle correct optionDifficulty 2 of 3qc029

A white precipitate obtained on adding dilute $H X_{2} SO X_{4}$ to a lead salt solution dissolves in hot concentrated ammonium acetate. This is because

Aweakly ionised lead(II) acetate/acetato complexes form, lowering $[Pb X^{2 +}]$ below the $K_{s p}$ of $PbSO X_{4}$
B $PbSO X_{4}$ is oxidised to $PbO X_{2}$
C $NH X_{4} X^{+}$ reduces $Pb X^{2 +}$ to $Pb$
D $PbSO X_{4}$ is converted to the more soluble $PbCl X_{2}$

PbSO X_{4}

is sparingly soluble, but acetate binds

Pb X^{2 +}

strongly as undissociated

Pb (CH X_{3} COO) X_{2}

and acetato complexes. This removes free

Pb X^{2 +}

, the ionic product falls below

K_{s p}

and the solid dissolves. No redox change occurs.