Given below are two statements :
Statement (I) : NaCl is added to the ice at , present in the ice cream box to prevent the melting of ice cream.
Statement (II) : On addition of NaCl to ice at , there is a depression in freezing point.
In the light of the above statements, choose the correct answer from the options given below :
Statement (I) : NaCl is added to the ice at , present in the ice cream box to prevent the melting of ice cream.
Statement (II) : On addition of NaCl to ice at , there is a depression in freezing point.
In the light of the above statements, choose the correct answer from the options given below :
- (A)Statement I is false but Statement II is true
- (B)Both Statement I and Statement II are true✓ Correct
- (C)Both Statement I and Statement II are false
- (D)Statement I is true but Statement II is false
Answer: (B)
Solution
Adding NaCl to ice creates a salt–ice slush whose equilibrium temperature drops well below , because dissolved NaCl depresses the freezing point of water — a colligative effect, . This colder brine surrounding the ice-cream container keeps the ice cream frozen far longer than plain ice at would, which is exactly why it is used in ice-cream boxes. Both statements are correct, and statement II is the mechanism behind statement I.
JEE Main · 2025 · 29 Jan 2025 · Shift 2 · Single correct option