2grams of a mixture of $N{a}_{2}C{O}_{3}andNaHC{O}_3$ on strong heating has suffered a mass loss of 0.62 gram. Percent weight of  $N{a}_{2}C{O}_3$ in the given mixture is

$2NaHC{O}_3\to N{a}_{2}C{O}_3+H_{2}O+C{O}_2$

168g of $NaHC{O}_3$ on heating suffers 62g of weight loss $H_{2}O+C{O}_2$

The amount of $NaHC{O}_3$ in the given mixture =$\frac{0.62}{62}\times 168=1.68g$

The amount of Na₂CO₃ in the given mixture =$2-1.68=0.32g$

Percentage of Na₂CO₃= 0.32$\times$100=32