Answer : The correct option is, (B) bimolecular
Explanation :
Molecularity : It is defined as the total number of reactant molecules taking part in the balanced equation of a reaction. It is a theoretical concept.
The given chemical reaction are,
Step (1) : [tex]I_2\rightarrow 2I[/tex]
Step (2) : [tex]I+H_2\rightarrow H_2I[/tex]
Step (3) : [tex]H_2I+I\rightarrow 2HI[/tex]
The number of reactants molecules taking part in the balanced equation of a reaction 2 are, [tex]I\text{ and }H_2[/tex].
In this reaction, 1 'I' molecules reacts with the 1 [tex]H_2[/tex] molecule.
Total number of reactant molecule = 1 + 1 = 2
The molecularity of the reaction is 2 that means, the elementary reaction is bimolecular.
Hence, the correct option is, (B) bimolecular
