For the reaction, ${\mathrm{H}}_{2\left(\mathrm{g}\right)}+{\mathrm{Br}}_{2\left(\mathrm{g}\right)}\rightleftharpoons 2{\mathrm{HBr}}_{\left(\mathrm{g}\right) }\mathrm{the} \mathrm{reaction} \mathrm{rate} =\mathrm{K}\left[{\mathrm{H}}_2\right] {\left[{\mathrm{Br}}_2\right]}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$Which statement is true about this reaction ?

The reaction is of second order

Molecularity of the reaction is 3/2

Order of the reaction is 3/2

Molecularity of the reaction is 2