Question

The gas $A_2$ in the left flask is allowed to react with gas $B_2$ presence in right flask as $A_2\left(g\right)+B_2\left(g\right)\rightleftharpoons 2AB\left(g\right);K_c=4$ at ${27}^{o}C$. What is the concentration of $AB$ when equilibrium is established?

• A. 1.33 M
• B. 2.66 M
• C. 0.66 M
• D. 0.33 M

Answer 1

Answer: (C)

0.66 M

The equilibrium recation is $A_2\left(g\right)+B_2\left(g\right)\rightleftharpoons 2AB\left(g\right).$

The number of moles at equilibrium of $A_2,.B_2$ and $AB$ are $(2-x)(4-x$) and $2x$ respectively.

The expression for the equilibrium constant is $K_c=\frac{4x^2}{(2-x)(4-x)}.$

$x=\frac{32}{24}=1.33mole$.

The equilibrium concentration $\left[AB\right(g\left)\right]=\frac{2\times 1.33}{4}=0.66M.$