What type of deviation is shown by a mixture of benzene and ethyl alcohol . Explain it .

Explanation

The mixture will show positive deviations form Raoults law as explained below Ethyl alcohol molecules are bonded together through hydrogen bonding . When benzene (or cyclohexane) is added to ethyl alcohol , the molecules of benzene (or cyclohexane) try to get in between the molecules of ethyl alcohol and break the hydrogen bonds. This reduces the ethyl alcohol - ethyl alcohol intermolecular attraction and the volume gets increased i.e., `Delta V _(mix") ` is + ve . Since some energy is used up in breaking the hydrogen bons . `Delta H_("mix")` is + ve . The decreased attraction between the molecules results in greater escaping tendency of each component which is reflected in increased vapour pressure of the mixture. As such a mixture of ethyl alcohol and benzene (or cyclohexane) show a positive deviation from Raoult.s law