# To a solution of a salt, $MgSO_4$ solution is added and white ppt. appears only on heating. The acid radical in the salt is

(a) $CO_3^{2-}$
(b) $HCO_3^-$
(c) $SO_3^{2-}$
(d) $C_2O_4^{2-}$

Answer: $HCO_3^-$

$2NaHCO_3 + MgSO_4 \longrightarrow Mg(HCO_3)_2 + H_2O + CO_2$
salt
On heating, $Mg(HCO_3)_2 \overset{\Delta}{\longrightarrow} MgCO_3 \downarrow + H_2O + CO_2$
$MgCO_3$ is the white ppt. which is obtained after heating $Mg(HCO_3)_2$
answered Jan 28, 2014