Dissolving 1.24 g of white phosphorous in boiling NaOH solution in an inert atmosphere gives a gas \(\mathbf{Q}\). The amount of \(\mathrm{CuSO}_{4}\) (in g) required to completely consume the gas \(\mathbf{Q}\) is ____. [Given : Atomic mass of \(\mathrm{H}=1, \mathrm{O}=16, \mathrm{Na}=23, \mathrm{P}=31, \mathrm{~S}=32, \mathrm{Cu}=63\) ]

JEE Advanced · 2022 · 28 Aug 2022 · Paper 1 · p-Block Elements

Dissolving 1.24 g of white phosphorous in boiling NaOH solution in an inert atmosphere gives a gas

Q

. The amount of

CuSO_{4}

(in g) required to completely consume the gas

Q

is ____.
[Given : Atomic mass of

H = 1, O = 16, Na = 23, P = 31, S = 32, Cu = 63

]

Answer: 2.38

Moles of

P_{4} = \frac{1.24}{124} = 0.01

mol.

Reaction with NaOH:

P_{4} + 3 NaOH + 3 H_{2} O \to PH_{3} + 3 NaH_{2} PO_{2}

From 0.01 mol

P_{4}

, we get 0.01 mol

PH_{3}

.

Reaction with

CuSO_{4}

2 PH_{3} + 3 CuSO_{4} \to Cu_{3} P_{2} + 3 H_{2} SO_{4}

From 0.01 mol

PH_{3}

, we need

\frac{3}{2} \times 0.01 = 0.015

mol

CuSO_{4}

.

Mass of

CuSO_{4} = 0.015 \times 159 = 2.385

JEE Advanced · 2022 · 28 Aug 2022 · Paper 1 · Numerical answer