Question

How will adding NaCl affect the freezing point of a solution? The freezing point will remain the same. The freezing point will increase. The freezing point will decrease. The solution will not freeze.

Answer 1

The freezing point will decrease

Answer 2

Answer:

The freezing point will decrease.

Explanation:

Whenever a solute is added to a solution/solvent, it leads to the depression in the freezing point of that solution/solvent. Depression in freezing point of a solution on addition of a solute is a colligative property. A colligative property is a physical property which depends upon the number of solute added not on the nature of solute that means it does not matter whether we are adding 1000 particles of sugar or salt in water, the depression in freezing point will occur by the same °C. Also, the more a solute is added the more will be the depression in freezing point.

The formula for depression in freezing point is mentioned as under:

               Δ T = K x m

where,    Δ T = freezing point depression;

                  K = cryoscopic constant;

                  m = molality of solution.

For example: The freezing point of water is 0 °C but as soon as we add a 92 gm solute like NaCl (common salt) in 1000 gm of water,  it's freezing point will lower to −3.72 °C.