Question

2 moles of PCl₅ were heated in a closed vessel of 2 litre capacity. At equilibrium, 40% of PCl₅ is dissociated into PCl₃ and Cl₂. The value of equilibrium constant is

• A. 0.266
• B. 0.53
• C. 2.66
• D. 5.3

Answer 1

Answer: (A)

0.266

Answer 2

At start, $\underset{2}{PCl_{5}}$⇌ $\underset{0}{PCl_{3}} + \underset{0}{Cl_{2}}$

At equilibrium. $\frac{2 \times 60}{100}$ $\frac{2 \times 40}{100}$ $\frac{2 \times 40}{100}$

Volume of cantainer = 2 litre

$\therefore$ $K_{c} = \frac{\frac{2 \times 40}{100 \times 2} \times \frac{2 \times 40}{100 \times 2}}{\frac{2 \times 60}{100 \times 2}}$ = 0.266