Question

A gaseous reaction $X_2(g) \to Y + \frac{1}{2} Z(g)$ There is increase in pressure from $100 \,mm$ to $120 \,mm$ in $5$ minutes. The rate of disappearance of $X_2$ is

• A. $8 \,mm \min ^{-1}$
• B. $2\, mm \min ^{-1}$
• C. $16\, mm \min ^{-1}$
• D. $4\, mm \min ^{-1}$

Answer 1

Answer: (A)

The increase in pressure shows the increase in conc. of $Z$.
Rate of appearance of $Z = \frac{120-100}{5}=4 \,mm \,min ^{-1}$
Rate of disappearance of $X_{2}=2 \times$ rate of appearance of $Z$
$=2 \times 4 \,mm \min ^{-1}=8\, mm \,\min ^{-1}$