Chemical and Ionic Equilibrium - Result Question 19

19. At constant temperature, the equilibrium constant $\left(K _p\right)$ for the decomposition reaction, $N _2 O _4 \rightleftharpoons 2 NO _2$, is expressed by $K _p=\frac{4 x^{2} p}{\left(1-x^{2}\right)}$, where, $p=$ pressure, $x=$ extent of decomposition. Which one of the following statement is true?

(2001, 1M)

(a) $K _p$ increases with increase of $p$

(b) $K _p$ increases with increase of $x$

(c) $K _p$ increases with decrease of $x$

(d) $K _p$ remains constant with change in $p$ and $x$