The weight (mg) of PbS that get precipitated form a 1.0 L saturated ${\text{PbSO}}_{\text{4}}$  solution if the    solution is made saturated with${\text{H}}_{\text{2}}\text{S}$  (0.1 M) and pH adjusted to 0 is Z. The value of $\frac{Z}{4}$  is _________.
(Round off to the nearest integer).
$[{\text{K}}_{\text{sp}}{\text{\hspace{0.17em}of\hspace{0.17em}PbSO}}_{\text{4}}{\text{=1.6×10}}^{\text{-8}}{\text{\hspace{0.17em}and\hspace{0.17em}K}}_{\text{sp}}{\text{\hspace{0.17em}of\hspace{0.17em}PbS=2.5×10}}^{\text{-27}}{\text{.\hspace{0.17em}For\hspace{0.17em}H}}_{\text{2}}{\text{S;\hspace{0.17em}K}}_{{\text{a}}_{\text{1}}}{\text{=10}}^{\text{-7}}{\text{\hspace{0.17em}and\hspace{0.17em}K}}_{{\text{a}}_{\text{2}}}{\text{=10}}^{\text{-14}}$  Atomic weight  Pb = 206 and S = 32