class 12

Missing

JEE Main

5 g of $Na_{2}SO_{4}$ was dissolved in x g of $H_{2}O$ . The change in freezing point was found to be $3.82_{∘}C$ . If $Na_{2}SO_{4}$ is $81.5%$ ionised , the value of x

($k_{f}$ for water =$1.86_{∘}C$ kg $mol_{−1}$) is apporximately :

(molar mass of S=32 g $mol_{−1}$ and that of Na=23 g $mol_{−1}$)