For a reaction: H₂ + Cl₂ + hv → 2HCl, Rate = k. (i) Write the order and molecularity of this reaction. (ii) Write the unit of k.
Solution:
The order of the reaction is 0. The reaction is bimolecular in nature. Thus, the molecularity is 2. The unit of the rate constant k is molL⁻¹s⁻¹ or mol.dm⁻³s⁻¹.