# A mixture of two salts is not water soluble but dissolves completely in dil. HCl to form a colourless solution. The mixture could be

(a) $AgNO_3$ and $KBr$
(b) $BaCO_3$ and $ZnS$
(c) $FeCl_3$ and $CaCO_3$
(d) $Mn(NO_3)_2$ and $MgSO_4$

Answer: $BaCO_3$ and $ZnS$
$BaCO_3$ + $ZnS$ mixture dissolves in HCl but is insoluble in water. Further the solution in HCl will be colourless.
edited Jan 29, 2014