White phosphorus disproportionates in alkali: P4 + 3NaOH + 3H2O -> PH3 + 3NaH2PO2. Taking the molar mass of P4 as 124 g mol^-1, find the mass (in g, two decimals) of P4 that corresponds to 0.350 equivalents in this reaction.

JEE Advanced levelNumerical answerDifficulty 3 of 3eq184

White phosphorus disproportionates in alkali: $P X_{4} + 3 NaOH + 3 H X_{2} O PH X_{3} + 3 NaH X_{2} PO X_{2}$ . Taking the molar mass of $P X_{4}$ as $124 g mo l^{- 1}$ , find the mass (in $g$ , two decimals) of $P X_{4}$ that corresponds to $0.350$ equivalents in this reaction.

Numerical answer type, answer in g, tolerance 0.02.

Three P atoms go

0 \to + 1

(3 electrons lost) while one P goes

0 \to - 3

(3 electrons gained), so n-factor of

P X_{4}

= 3

. Equivalent mass

= 124/3 = 41.33

. Mass

= 0.350 \times 41.33 = 14.467 g