Question

For the reaction, $H_{2\left(g\right)}+Br_{2\left(g\right)}$ $\rightarrow$ $2HBr\left(g\right)$, the reaction rate $=k\left[H_{2}\right]$ $\left[Br_{2}\right]^{1 /2}$. Which statement is true about this reaction?

• A. The reaction is of second order.
• B. Molecularity of the reaction is 3/2.
• C. The unit of $k$ is $sec^{-1} $.
• D. Molecularity of the reaction is 2.

Answer 1

Answer: (D)

Explanation:
$H _{2}(g)+ Br _{2}(g) \longrightarrow 2 HBr (g)$
The molecularity of the reaction is $1+1=2$
Rate of reaction $=K\left[H_{2}\right]\left[B r_{2}\right]^{1 / 2}$
Order of reaction $=1+\frac{1}{2}=\frac{3}{2}$
Unit of $K=mol^{-1 / 2} L^{1 / 2} s^{-1}$