Question

An equilibrium mixture of $N_2$, $H_2$, and $N{H}_3$ at $700K$contains $0.036M{N}_2$ and $0.15M$ $H_2$. At this temperature, $K_c$ for the reaction $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$ is $0.29$. What is the concentration of $N{H}_3$?

• A. $5.9\times {10}^{-3}M$
• B. $6.0\times {10}^{-3}M$
• C. $6.4\times {10}^{-3}M$
• D. $6.9\times {10}^{-3}M$

Answer 1

The correct option is A $5.9\times {10}^{-3}M$

As we know,

$N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right)$

$K_c=C_{N{H}_3}^2/(C_{N_2}\times C_{H_2}^3)=0.29$

$C_{N{H}_3}^2=0.29\times 0.036\times {0.15}^3=0.000035235$

$C_{N{H}_3}=5.9\times {10}^{-3}M.$