Question

Roasting of ZnS at ${700}^{\circ }$ C liberates a gas that usually turns lime water milky. Name the gas.

Answer 1

$S{O}_2$ turns lime water milky.
$CaS{O}_3$ is also a white ppt. insoluble in water. Therefore, yes, it will turn limewater milky.
This is the same principle as to carbon dioxide:
Calcium sulfite is insoluble, thus precipitating, in saturated $Ca(OH{)}_2$ solution.
$C{a}_2++2O{H}^{-}+S{O}_2\to CaS{O}_3,precip.+H_{2}O$
Compare:
$C{a}_2++2O{H}^{-}+C{O}_2\to CaC{O}_3,precip.+H_{2}O$