JEE Chemistry 2025 Question with Solution

Given: Two statements about adding NaCl to ice at $0^\circ C$.

Find: Which statement(s) is/are correct.

Adding NaCl to ice causes freezing point depression, which is a colligative property. Because of this, the ice-water mixture can exist at a temperature below $0^\circ C$.

Therefore, the mixture around the ice cream becomes colder, which helps prevent the ice cream from melting.

So, Statement (I) is true and Statement (II) is also true.

Therefore, the correct option is B.

Given:

• Statement (I): NaCl is added to the ice at $0^\circ C$, present in the ice cream box to prevent the melting of ice cream.
• Statement (II): On addition of NaCl to ice at $0^\circ C$, there is a depression in freezing point.

Find: The correct option.

Step 1: Understand the effect of adding salt to ice.

When NaCl is added to ice, it dissolves in the thin layer of water present on the surface of ice. This lowers the freezing point of water.

Step 2: Analyze Statement (I).

Because the freezing point decreases, the ice-salt mixture can remain at a temperature below $0^\circ C$. This lower temperature helps keep the ice cream frozen. Hence, Statement (I) is true.

Step 3: Analyze Statement (II).

The lowering of freezing point on adding a solute is called freezing point depression. This is a colligative property. Hence, Statement (II) is true.

Step 4: Conclusion.

Both statements are correct. Statement (I) gives the practical application, and Statement (II) gives the reason.

Therefore, the correct option is B.