Q. 28 g of $N_{2}$ and 6 g of $H_{2}$ were kept at $400℃$ in 1 L vessel, the equilibrium mixture contained 27.54 g of $NH_{3}$. The approximate value of $K_{c}$ for the above reaction can be $(in\ mol^{- 2}L^{2})$

A) 25
B) 50
C) 75
D) 100
Explanation

(c)
$N_{2}\ + \ \ \ 3H_{2} \rightleftharpoons \ \ \ \ 2{NH}_{3}$
1 3 0 initially
$1 - 0.81\ \ \ 3 - 2.43$
$\left( \mathbf{=}0.19 \right)\left( \mathbf{=}0.57 \right)\ \ 1.62$ at equilibrium
Number of moles of $N_{2} = \frac{28}{28} = 1\ mol$
Number of moles of $H_{2} = \frac{6}{2} = 3\ mol$
Number of moles of $NH_{3} = \frac{27.54}{17} = 1.62\ mol$
$\mathbf{\therefore\ }K_{c} = \frac{\left\lbrack NH_{3} \right\rbrack^{2}}{\left\lbrack N_{2} \right\rbrack\left\lbrack H_{2} \right\rbrack^{3}} = \frac{\lbrack 1.62\rbrack^{2}}{\lbrack 0.19\rbrack\lbrack 0.57\rbrack^{3}} = 75$

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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