Q. A mixture of 0.3 mole of $H_{2}$ and 0.3 mole of $I_{2}$ is allowed to react in a 10 L evacuated flask at $500℃$. The reaction is $H_{2} + I_{2} \rightleftharpoons 2HI,$ the $K$ is found to be 64. The amount of unreacted $I_{2}$ at equilibrium is

A) 0.03 mol
B) 0.06 mol
C) 0.09 mol
D) 3.6 mol
Explanation

(b)
$K_{c} = \frac{\lbrack HI\rbrack^{2}}{\left\lbrack H_{2} \right\rbrack\lbrack I_{2}\rbrack}$
$\therefore 64 = \frac{x^{2}}{0.03 \times 0.03}$
$\therefore x^{2} = 64 \times 9 \times 10^{- 4}$
or, $x = 8 \times 3 \times 10^{- 2}$
$x$ is the amount of HI
At equilibrium, amount of $I_{2}$ will be
$0.30 - 0.24 = 0.06$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

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