Question

Choose the incorrect statment for a solution showing positive deviation:

• A. Solvent-solute interaction is less than the solvent-solvent and the solute-solute interactions
• B. Enthalpy of mixing is greater than zero i.e. $\Delta H_{mix}>0$
• C. Entropy of mixing is less than zero i.e. $\Delta S_{mix}<0$
• D. Gibbs free energy of mixing is less than zero i.e. $\Delta G_{mix}<0$

Answer 1

The correct option is C Entropy of mixing is less than zero i.e. $\Delta S_{mix}<0$

Positive deviation:
Solvent-solute interaction is less than the solvent-solvent and the solute-solute interactions

For positive deviation:

$\Delta H_{mix}>0$
$\Delta S_{mix}>0$
$\Delta G_{mix}<0$
Examples: Ethanol and Acetone, $C{S}_2$ and acetone

Negative deviation:
Solvent-solute interaction is more than the solvent-solvent and the solute-solute interactions.

$\Delta H_{mix}<0$
$\Delta S_{mix}>0$
$\Delta G_{mix}<0$
Examples: Phenol and aniline, $CHC{l}_3$ and Acetone