In a solvent 50% of benzoic acid dimerises while rest ionises, determine molar mass of acid which is observed and also its van't Hoff factor.

Explanation

To solve the problem, we need to determine the observed molar mass of benzoic acid and its van't Hoff factor based on the information provided.

### Step-by-Step Solution:

1. **Understanding Dimerization and Ionization**:
- We know that 50% of benzoic acid dimerizes and the rest ionizes.
- Dimerization means two molecules of benzoic acid combine to form one dimer (A2), while ionization means that benzoic acid dissociates into ions.

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