Question

In pseudo-unimolecular reactions:

• A. one of the reactants is present in large excess
• B. both the reactants have same concentration
• C. both the reactants are present in low concentration
• D. one of the reactants is less reactive

Answer 1

The correct option is A one of the reactants is present in large excess

The reactions having molecularity but order of reaction is one are called pseudo unimolecular reactions. In pseudo unimolecular reaction one recatent is always in excess amount. Due to its excess amount there is no significant changes in its comcetatration that's why rate of reaction only depend on second recatent.

Ex. Hydrolysis of ester in water. In this water is in excess.

So answer will be A