Question

What volume of hydrogen gas, at 273 K and 1 atm pressure will be consumed in obtaining 21.6 g of elemental boron (atomic mass = 10.8) from the reduction of boron trichloride by hydrogen?
(A) 22.4 L
(B) 89.6 L
(C) 67.2 L
(D) 44.8 L

Answer 1

The correct answer is

67.2

Answer 2

Answer:

(C) 67.2 L

Explanation:

As per the question,

The balanced equation of boron trichloride by hydrogen is

2BCl₃ + 3H₂ ⇒ 2B + 6HCl

That is 2 mol of boron trichloride  = 21.6 gm = 3 mol of hydrogen

According to ideal gas equation:

PV = nRT

Where,

P = pressure

V =volume

R= universal gas constant

T = temperature

n = number of moles of gas

$V=\frac{nRT}{P}$

Put all the value given:

$V=\frac{3 \times 0.0821 \times 273}{1}$

V = 67.2 L

Therefore, volume of hydrogen gas =67.2 L

Hence, the correct option is (C).