A system of greater disorder of molecules is more probable. The disorder of molecules is reflected by the entropy of the system. A liquid vapourizes to form a more disordered gas. When a solute is present, there is additional contribution to the entropy of the liquid due to increased randomness. As the entropy of solution is higher than that of pure liquid, there is weaker tendency to form the gas. Thus, a solute (non-volatile) lowers the vapour pressure of a liquid, and hence a higher boiling point of the solution.
Similarly, the greater randomness of the solution opposes the tendercy to freeze. In consequence, a lower temperature must be reached for achieving the equilibrium between the solid (frozen solvent) and the solution. The elevation in boiling point `(DeltaT_(b))` and depression in freezing point `(DeltaT_(f))` of a solution are the colligative properties which depend only on the concentration of particles of the solute and not their identity. For dilute solutions, `(DeltaT_(b))` and `(DeltaT_(f))` are proportional to the molarity of the solute in the solution.
A mixture of two immiscible liquids at a constant pressure of `1.0 atm` boils at temperature

Options

A. Equal to the normal boiling point of more volatile liquid.
B. Equal to the mean of the normal boiling points of the two liquids.
C. Greater than normal boiling point of either of liquids.
D. Smaller than the normal boiling point of either of the liquid.

Answer

D

Explanation

Mixture will boil at lower temperature of the boiling point of either liquid.