Question

Reaction of chloroform with chlorine is an example of fraction order reaction. Its rate law expression is rate $=k\left[ CHCl _{3}\right]\left[ Cl _{2}\right]^{1 / 2}$. If both are assumed in gaseous state and pressure is measured in bar then units of rate and rate constant respectively are

• A. bar $\min ^{-1}$, bar $^{2} \min ^{-1}$
• B. bar $\min ^{-1}, \text{bar}^{-1 / 2}, \min ^{-1}$
• C. $\text{bar}^{-1 / 2}, \min ^{-1}, \text{bar}^{2} \min ^{-1}$
• D. bar $\min ^{-1}$, bar $^{-1 / 2} \min ^{-1}$

Answer 1

Answer: (B), (D)

Given, rate $=k\left[ CHCl _{3}\right]\left[ Cl _{2}\right]^{1 / 2}$
Order $=1+\frac{1}{2}=\frac{3}{2}$
So, units of rate constant $=\frac{\text { Units of rate }}{\left[ CHCl _{3}\right]\left[ Cl _{2}\right]^{1 / 2}}=\frac{\text{bar min}^{-1}}{\text{bar}^{3 / 2}}$
Units of rate is bar $\min ^{-1}$.