Which requires catalyst ?

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

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

In which process, a catalyst is not used :

Explain bromination of benzene requires FeBr_3 as catalyst, while bromination of anisole (C_6H_5OCH_3) does not require any catalyst.

The temperature at which the catalystic activity of the catalysts is maximum ,is called