Question

The boiling point of an azeotropic mixture of water and ethyl alcohol is less than that of the theoretical value of water alcohol mixture. Hence the mixture shows

• A. The solution is highly saturated.
• B. Positive deviation from Raoult's law.
• C. Negative deviation from Raoult's law.
• D. Nothing can be said.

Answer 1

Answer: (B)

(b) Positive deviations from Raoult's law are noticed when
(i) Experimental value of vapor pressure of mixture is more than calculated value.
(ii) Experimental value of boiling point of mixture is less than the calculated value.
(iii) $\Delta_{\text {mixing }} H =+ ve$
(iv) $\Delta_{\text {mixing }} V=+v e$