Question

In the following hypothetical reaction, $A+3 B \rightleftharpoons 2 C+D$ initial moles of $A$ are twice as that of $B$. If at equilibrium moles of $B$ and $C$ are equal. Percentage of $B$ reacted is

• A. $60 \%$
• B. $40 \%$
• C. $10 \%$
• D. $20 \%$

Answer 1

Answer: (A)

Given that at equilibrium,

$x-3 y=2 y, x=2 y+3 y=5 y$

Moles of $B$ reacted $=3 y$

$\%=\frac{\text { Moles reacted }}{\text { Total moles }} \times 100=\frac{3 y}{x} \times 100=\frac{3 y}{5 y} \times 100$

$=60 \%$