Question

In which of the following case $K_p = K_c$ ?

• A. $N _2+3 H _2 \rightleftharpoons 2 NH _3$
• B. $PCl _5 \rightleftharpoons PCl _3+ Cl _2$
• C. $N _2+ O _2 \rightleftharpoons 2 NO$
• D. $2 SO _2+ O _2 \longrightarrow 2 SO _3$

Answer 1

Answer: (C)

$K_{p}=K_{c}\left(RT\right)^{\Delta n}$, where $\Delta n$ = change in gaseous molecules
$N_{2}+3H_{2} \rightleftharpoons 2NH_{3} ; \Delta n=-2 $
$\therefore k_{p}<\, k_{c}$
$N_{2}+O_{2} \rightleftharpoons 2NO; \Delta n=0$
$\therefore k_{p}=k_{c}$
$2SO_{2}+O_{2} \rightleftharpoons 2SO_{3} ; \Delta n=-1 $
$\therefore K_{p}<\, K_{c}$