0.46 g of sodium is dissolved completely in liquid ammonia (the solution is kept free of catalyst), and excess NH4Cl is then added. What volume of H2 is liberated at STP? (Na = 23, molar volume 22.4 L/mol)

JEE Advanced levelSingle correct optionDifficulty 3 of 3sb039

$0.46 g$ of sodium is dissolved completely in liquid ammonia (the solution is kept free of catalyst), and excess $NH X_{4} Cl$ is then added. What volume of $H X_{2}$ is liberated at STP? (Na = 23, molar volume 22.4 L/mol)

Sodium gives one solvated electron per atom:

0.46/23 = 0.020

mol electrons.

2 NH X_{4} Cl + 2 Na 2 NaCl + 2 NH X_{3} + H X_{2}

shows that 2 electrons give 1

H X_{2}

, so

0.010

mol

H X_{2}

forms. Volume =

0.010 \times 22400 = 224 mL