Question

The equilibrium constant, Kp, has a value of 6.5 × 104 at 308 K for the reaction of nitrogen monoxide with chlorine. 2NO(g) + Cl2(g) 2NOCl(g) [Balanced] What is the value of Kc

Answer 1

Answer: The $K_c$ for the given reaction is $2.67\times 10^{-2}$

Explanation:

For the given chemical equation:

$2NO(g)+Cl_2\rightleftharpoons 2NOCl(g)$

Relation of $K_p\text{ with }K_c$ is given by the formula:

$K_p=K_c(RT)^{\Delta n_g}$

where,

$K_p$ = equilibrium constant in terms of partial pressure = $6.5\times 10^{-4}$

$K_c$ = equilibrium constant in terms of concentration = ?

R = Gas constant = $0.0821\text{ L atm }mol^{-1}K^{-1}$

T = temperature = 308 K

$\Delta n_g$ = change in number of moles of gas particles $n_{products}-n_{reactants}=2-3=-1$

Putting values in above equation, we get:

$6.5\times 10^{-4}=K_c\times (0.0821\times 500)^{-1}\\\\K_c=\frac{6.5\times 10^{-4}}{(0.0821\times 500)^{-1})}=2.67\times 10^{-2}$

Hence, the $K_c$ for the given reaction is $2.67\times 10^{-2}$