Which of the following compounds is used as an antifreeze in the radiator of the vehicle?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Glycol
A 35% (v/v) solution of ethylene glycol in water is used as an antifreeze in car radiators. As a non-volatile solute it lowers the freezing point of water (to about 255.4 K), so the coolant does not freeze in cold weather. Being non-volatile, it is not lost by evaporation while the engine is hot.
NCERT (2026-27 edition):
Expressing Concentration of Solutions – “… Volume percentage (V/V): The volume percentage is defined as: Volume % of a component = (Volume of the component / Total volume of solution) × 100. For example, 10% ethanol solution in water means that 10 mL of ethanol is dissolved in water such that the total volume of the solution is 100 mL. Solutions containing liquids are commonly expressed in this unit. For example, a 35% (v/v) solution of ethylene glycol, an antifreeze, is used in cars for cooling the engine. At this concentration the antifreeze lowers the freezing point of water to 255.4K (–17.6°C).”
Note: The same/similar question has been asked in different years by NTA as per the details given below:
| 2026 | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| – | – | – | 02-06 S3 31-05 S1 | – |