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Molecules of benzoic acid (C 6 H 5 COOH) dimerise in benzene. 'w' g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2K. If the percentage association of the acid to form dimmer in the solution is 80, then w is – (Its given that K f = 5 K kg mol–1, Molar mass of benzoic acid = 122 g mol –1 )

1. 1.5 g
2. 1.8 g
3. 1.0 g
4. 2.4 g

Correct answer: 2.4 g

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