The Molal Freezing-Point Depression Constants for Benzene and Water Are

Multiple Choice

The molal freezing-point depression constants for benzene and water are 5.12 and 1.86, respectively. When 4.6 g of formic acid (HCOOH) is dissolved in 1.0 kg of benzene, the freezing point is depressed by 0.26°C. When the same amount of formic acid is dissolved in 1.0 kg of water, the freezing point is lowered by 0.19°C. To explain these results, we must assume that

A) formic acid is monomeric in benzene and associated in water.
B) formic acid is associated in benzene and monomeric in water.
C) formic acid is monomeric in benzene and dissociated in water.
D) formic acid is dissociated in benzene and monomeric in water.