Question

Eight mole of a gas $AB _{3}$ attain equilibrium in a closed container of , volume $1 dm ^{3}$ as, $2 AB _{3} \rightleftharpoons A _{2}( g )+3 B _{2}( g ) $ If at equilibrium $2 mole$ of $A_{2}$ are present then, equilibrium constant is:

• A. $72 \,mol ^{2} L ^{-2}$
• B. $36 \,mol ^{2} L ^{-2}$
• C. $3 \,mol ^{2} L ^{-2}$
• D. $27\, mol ^{2} L ^{-2}$

Answer 1

Answer: (D)

Thus, $K_{c}=\frac{\left[A_{2}\right]\left[B_{2}\right]^{3}}{\left[A B_{3}\right]^{2}}$;

Also, $\frac{a}{2}=2$

$\therefore a=4$

$\therefore \left[A B_{3}\right]=\frac{4}{1} ;\left[A_{2}\right]=\frac{2}{1} ;\left[B_{2}\right]=\frac{6}{1}$

Thus, $K_{c}=\frac{2 \times 6^{3}}{4^{2}}$
$=27 \,mol ^{2} \,L^{-2}$