Question

In which of the following equilibrium $ K_c $ and $ K_p $ are not equal?

• A. $2 NO _{( g )} \rightleftharpoons N _{2}( g )+ O _{2}( g )$
• B. $SO _{2}( g )+ NO _{2}( g ) \rightleftharpoons SO _{3}( g )+ NO _{( g )}$
• C. $H _{2( g )}+ I _{2}( g ) \rightleftharpoons 2 HI _{( g )}$
• D. $2 C _{( s )}+ O _{2}( g ) \rightleftharpoons 2 CO _{2}( g )$

Answer 1

Answer: (D)

The reaction for which the number of moles of gaseous products $\left(n_{p}\right)$ is not equal to the number of moles of gaseous reactants $\left(n_{R}\right)$, has different value of $K_{C}$ and $K_{P}$
From the equation, $K_{P}=K_{C} \times(R T)^{\Delta n_{g}}$
where, $\left[\Delta n_{g}\right.$ gaseous $\left.=n_{P}-n_{R}\right]$
(a) $n_{P}=n_{R}=2$ thus, $K_{P}=K_{C}$
(b) $n_{P}=n_{R}=2$ thus, $K_{P}=K_{C}$
(c) $n_{P}=n_{R}=2$ thus, $K_{P}=K_{C}$
$(d) n_{P}=2, n_{R}=1$ thus, $K_{P} \neq K_{C}$