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 g) from the reduction of boron trichloride by hydrogen ?

(a) 67.2 L

(b) 44.8 L

(c) 22.4 L

(d) 89.6 L

Answer 1

Correct option is (a) 67.2 L

Answer 2

Correct option is (a) 67.2 L

 \(2BCl_3 +3H_2\longrightarrow2B+6HCl\)

Number of moles of \(B=\frac{21.6}{10.8}=2\) mol.

\(\because\) 2 moles of B produced by 3 mol of Hydrogen.

\(\therefore\) volume of \(H_2\) at 273 k and 1 atm pressure.

PV = nRT

\(V=\frac{3\times0.082\times273}{1}\)

\(V=67.16\)

\(V=67.2\,L.\)