Question

For a reaction, $NO (g)+ O _{2}(g) \rightarrow 2 NO _{2}(g) ;$ Rate $=k l[N O]^{2}\left[O_{2}\right]$. If the volume of the reaction vessel is doubled, the rate of reaction

• A. will diminish to 1/4 of initial value
• B. will diminish to 1/8 of initial value
• C. will increase 4 times
• D. will increase 8 times

Answer 1

Answer: (B)

will diminish to 1/8 of initial value

Answer 2

Rate $\propto$ concentration $\propto \frac{\text { moles }}{\text { litre }}$ When the volume of the reaction vessel is doubled then the rate of reaction $\left(r^{1}\right)$ will be
$r=k\left[\frac{x}{V}\right]^{2}\left[\frac{y}{V}\right]$
(where, $x$ and $y$ are the number of moles of NO and $\left.O_{2}\right)$
$I=k\left[\frac{x}{2 V}\right]^{2}\left[\frac{y}{2 V}\right] \frac{I}{r}$
$=\frac{k\left[\frac{x}{2 V}\right]^{2}\left[\frac{y}{2 V}\right]}{k\left[\frac{x}{V}\right]^{2}\left[\frac{y}{V}\right]}$
$\Rightarrow r \frac{1}{8} r$