Question

In cold countries, ethylene glycol is added to water in the radiators of cars during winters. It results in:
A.Lowering in boiling point
B.Reducing viscosity
C.Reducing specific heat
D.Lowering in freezing point

Answer 1

We must remember that the ethylene glycol is used in the cooling of a car radiator during winter. The specific warmth of antifreeze is lower than that of puree water. Its role in an automobile is to soak up heat from the engine.

Complete step by step answer:
As we know that the vapour pressure of pure water will be lowered when a solute is added. According to the Raoult’s law, that the mole fraction present in the component is directly proportional to its partial vapour pressure of each component
When a non-volatile solute is added to the solvent, there is a decrease in vapour pressure and it becomes equal to that of solid solvent at a lower temperature then the freezing point of solvent gets decreased.
On the other hand, the addition of ethylene glycol to water, increases the boiling point significantly. Addition of glycol lowers the freezing point of water in the radiator so that the cold winter temperature wouldn’t burst the lines and thus, glycol-water mixture is used as antifreeze in radiators of cars.

Therefore, the solution to this present question is option D that is lowering in freezing point.

Note:
We must remember that the molar depression constant is a depression in freezing point when one mole of solute is added to 1kg of solvent which can be calculated after the addition of solute, we can calculate the molar depression from the freezing point of solution and pure solvent. Lowering of freezing point is directly proportional to molality.