The equilibrium $N X_{2} O X_{4} (g) 2 NO X_{2} (g)$ in a cylinder is compressed isothermally to half its volume and a new equilibrium is reached. Compared with the original equilibrium

Athe amount of $NO X_{2}$ is lower, $[NO X_{2}]$ is also lower and $K_{c}$ is the same
Bthe amount of $NO X_{2}$ is higher, $[NO X_{2}]$ is higher and $K_{c}$ is the same
Cthe amount of $NO X_{2}$ is lower, $[NO X_{2}]$ is higher and $K_{c}$ is the same
Dthe amount of $NO X_{2}$ is lower, $[NO X_{2}]$ is higher and $K_{c}$ is lower

Answer: C

Compression favours the side with fewer gas moles, so the amount of

NO X_{2}

falls. But the volume is halved and the shift is only partial, so the concentration of

NO X_{2}

ends up higher than before.

K_{c}

is constant at constant temperature.