Question

For a gaseous reaction $2 A + B \rightleftharpoons C + D$, the partial pressures of $A , B , C$ and $D$ at equilibrium are $0.5$, $0.8,0.7$ and $1.2 \,atm$. The value of $K _{ p }$ for this reaction is

• A. $2.4 \,atm$
• B. $6.2\, atm ^{-2}$
• C. $4.2\, atm ^{-1}$
• D. $8.4\, atm ^{-3}$

Answer 1

Answer: (C)

The equilibrium constant for the reaction in terms of partial pressure
$K _{ p }=\frac{\left( P _{ e }\right) \times\left( P _{ D }\right)}{\left( P _{ A }\right)^{2} \times\left( P _{ B }\right)}$
$=\frac{0.7 \times 1.2}{(0.5)^{2} \times 0.8}$
$=4.2 \,atm ^{-1}$