Question

The degree of dissociation of $S{O}_3$ is $\alpha$ at equilibrium pressure $P_0$:
$K_p$ for $2S{O}_3\left(g\right)\rightleftharpoons 2S{O}_2\left(g\right)+O_2\left(g\right)$

• A. $\left[\right(P_0{\alpha }^3\left)/2\right(1-\alpha {)}^3]$
• B. $\left[\right(P_0{\alpha }^3\left)/\right(2+\alpha \left)\right(1-\alpha {)}^2]$
• C. $\left[\right(P_0{\alpha }^2\left)/2\right(1-\alpha {)}^2]$
• D. none of these

Answer 1

The correct option is B $\left[\right(P_0{\alpha }^3\left)/\right(2+\alpha \left)\right(1-\alpha {)}^2]$

Reaction:
$2S{O}_3\left(g\right)\rightleftharpoons 2S{O}_2\left(g\right)+O_2\left(g\right)$
$P(1-\alpha )$ $P\alpha$ $\frac{P\alpha }{2}$
$P[1+\frac{\alpha }{2}]=P_0$
$K_P=\frac{\left(P^2{\alpha }^2\right)\left[P\frac{\alpha }{2}\right]}{P^2(1-{\alpha }^2)}=\frac{P_0{\alpha }^3}{(2+\alpha )(1-\alpha {)}^2}$