Question

The reaction $A\left(g\right)+B\left(g\right)$ $\rightleftharpoons$ C (g) + D (g) is studied in a one litre vessel at ${250}^{0}C$.The initial concentration of $A$ was $3n$ and that of $B$ was $n$.

When equilibrium was attained, the equilibrium concentration of $C$ was found to the equal to the equilibrium concentration of $B$. What is the concentration of $D$ at equilibrium?

• A. $n/2$
• B. $(3n-1/2)$
• C. $(n-n/3)$
• D. $n$

Answer 1

The correct option is A $n/2$

The given reaction is,

$A\left(g\right)+B\left(g\right)\rightleftharpoons C\left(g\right)+D\left(g\right)$

$3nn003n-xn-xxx$

The equillibrium concentration of $C$ is equal to the concentration of $B$

$n-x=x$

$2x=nx=\frac{n}{2}$

Thus, the equilibrium concentration of $D$ is $x=\frac{n}{2}$

So, the correct option is $A$