Question

In which one of the following reactants, $K_p$ is less than $K_c$?

• A. $2S{O}_3\left(g\right)\rightleftharpoons 2S{O}_2\left(g\right)+O_2\left(g\right)$
• B. $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
• C. $PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
• D. $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$

Answer 1

The correct option is B $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$

$K_p$ is less than $K_C$ for$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
$△$n = number of moles of gaseous products - number of moles of gaseous reactants
$△n=2-(2+1)$
$△n=-1$
$K_p=K_c(RT{)}^{△n}$
$K_p-K_c(RT{)}^{-1}$
$K_p=\frac{K_c}{RT}$
$RT>1$
$\frac{1}{RT}<1$
$\therefore K_p<K_c$