Question

Assuming complete association, van't Hoff factor for $C{H}_{3}COOH$ in benzene is:

• A. 0.5
• B. 1
• C. 1.5
• D. 2

Answer 1

The correct option is A 0.5

Molecules of ethanoic acid dimerise in benzene due to hydrogen bonding. This normally happens in solvents of low dielectric constant. In this case number of particles are reduced due to dimerisation.
Association of molecules is depicted as follows:

Here $i=0.5$