Q. For the reaction, $H_{2} + I_{2} \rightarrow 2HI$, the differential rate law is
A) $- \frac{d\left\lbrack H_{2} \right\rbrack}{dt} = - \frac{d\lbrack I_{2}\rbrack}{dt} = \frac{1}{2}\frac{d\lbrack HI\rbrack}{dt}$
B) $- \frac{d\left\lbrack H_{2} \right\rbrack}{dt} = - 2\frac{d\lbrack I_{2}\rbrack}{dt} = \frac{1}{2}\frac{d\lbrack HI\rbrack}{dt}$
C) $- \frac{d\left\lbrack H_{2} \right\rbrack}{dt} = - \frac{d\lbrack I_{2}\rbrack}{dt} = \frac{d\lbrack HI\rbrack}{dt}$
D) $- \frac{d\left\lbrack H_{2} \right\rbrack}{dt} = - \frac{d\left\lbrack I_{2} \right\rbrack}{dt} = - \frac{d\lbrack HI\rbrack}{dt}$
Explanation
(a)
$H_{2} + I_{2} \rightarrow 2HI$
Rate of reaction,
$= \frac{- d\left\lbrack H_{2} \right\rbrack}{dt} = \frac{- d\lbrack I_{2}\rbrack}{dt} = \frac{1}{2}\frac{d\lbrack HI\rbrack}{dt}$
$Or\ \ \ \ \ \ \ \ \ = \frac{- 2d\left\lbrack H_{2} \right\rbrack}{dt} = \frac{- 2d\lbrack I_{2}\rbrack}{dt} = \frac{d\lbrack HI\rbrack}{dt}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.