Question

For the reaction,

$2N{O}_2\left(g\right)$ $\rightleftharpoons$ $2NO\left(g\right)$ $+$ $O_2\left(g\right)$; $K_c$ $=$ $1.8\times {10}^{-6}$ at ${185}^{0}C$.

At ${185}^{0}C$, the $K_c$ for $NO$ $\left(g\right)$ $+$ $\frac{1}{2}{O}_2\left(g\right)$ $\rightleftharpoons$ $N{O}_2\left(g\right)$ is ______.

• A. $1.95\times {10}^{-3}$
• B. $1.95\times {10}^3$
• C. $7.5\times {10}^2$
• D. $0.9\times {10}^6$

Answer 1

The correct option is C $7.5\times {10}^2$

$2N{O}_2\left(g\right)$ $\rightleftharpoons$ $2NO\left(g\right)$ $+$ $O_2\left(g\right)$; $K_c$ $=$ $1.8\times {10}^{-6}$ at ${185}^{0}C$...........(1)

At ${185}^{0}C$, the $K_c$ for $NO$ $\left(g\right)$ $+$ $\frac{1}{2}{O}_2\left(g\right)$ $\rightleftharpoons$ $N{O}_2\left(g\right)$ is .......(2)

reaction 2 is formed when 1/2 and opposite of reaction (1)

so Kc of reaction (2)is

= $\frac{1}{(k1{)}^{1/2}}$

= $7.5x{10}^2$