# Among the following reactions of hydrogen with halogens,

Question:

Among the following reactions of hydrogen with halogens, the one that requires a catalyst is :

1. $\mathrm{H}_{2}+\mathrm{I}_{2} \rightarrow 2 \mathrm{HI}$

2. $\mathrm{H}_{2}+\mathrm{F}_{2} \rightarrow 2 \mathrm{HF}$

3. $\mathrm{H}_{2}+\mathrm{Cl}_{2} \rightarrow 2 \mathrm{HCI}$

4. $\mathrm{H}_{2}+\mathrm{Br}_{2} \rightarrow 2 \mathrm{HBr}$

Correct Option: 1

Solution:

$\mathrm{H}_{2}+\mathrm{I}_{2} \rightarrow 2 \mathrm{HI}$