Question

24-45. The molar enthalpies of mixing of solutions of tetrahydrofuran and trichloromethane at 25°C are listed below AH/J-mol- XTHF mix 0.0568 -0.469 0.1802 -1.374 0.3301 -2.118 0.4508 -2.398 0.5702 -2.383 0.7432 -1.888 0.8231 -1.465 0.9162 -0.802 Do tetrahydrofuran and trichloromethane form a regular solution?

Answer 1

Ans:

Ideal solution : Liquid-liquid solutions which obeys Raoult’s law over entire range of concentrations. For an ideal solution enthalpy of mixing will be zero.

Regular solution: (Non-ideal solution): Liquid-liquid solutions which does not obey Raoult’s law over entire range of concentrations. For a regular solution enthalpy of mixing will be non-zero (It may be positive or negative)

Positive enthalpy of mixing/positive molar enthalpy of mixing means it is a positive deviation from Raoult’s law.

Negative enthalpy of mixing/negative molar enthalpy of mixing means it is a negative deviation from Raoult’s law.

• Since molar enthalpy of mixing is negative for Tetrahydro furan and trichloromethane, it forms a regular solution with negative deviation from Raoult’s law.