The mass percentage of water in Glauber's salt, Na2SO4.10H2O (Na 23, S 32, O 16, H 1), is closest to

JEE Main levelSingle correct optionDifficulty 2 of 3sb096

The mass percentage of water in Glauber's salt, $Na X_{2} SO X_{4} \cdot 10 H X_{2} O$ (Na 23, S 32, O 16, H 1), is closest to

Molar mass is

142 + 180 = 322

g/mol, of which water is 180 g. Percentage

= 180/322 \times 100 = 55.9

. The value 44.1 is the anhydrous salt fraction.