Question

In which of the following reaction, the value of $K_p$ will be equal to $K_c$?

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

Answer 1

Answer: (A)

$H_2+I_2\rightleftharpoons 2HI$

$K_P=K_C{\left(RT\right)}^{△n}$

$K_P=K_C$ if $△n=0$

where $△n=$ number of moels of gaseous product - number of moles of gaseous reactant

$\left(A\right)△n=2-2=0$

$\left(B\right)△n=2-0=2$

$\left(C\right)△n=4-2=2$

$\left(D\right)△n=2-3=-1$