role of ethylene glycol in the radiator of vehicles is to

Options

A. Decrease the freezing point of water in the winter and increase the boiling point of water in the summer
B. Only decrease the freezing point of water
C. Only increase the boiling point of water
D. Prevent corrosionof automobile parts

Answer

### Step-by-Step Solution:

1. **Understanding the Role of Ethylene Glycol**: Ethylene glycol is commonly used in vehicle radiators as a coolant. Its primary function is to manage the temperature of the engine by preventing overheating and freezing.

2. **Freezing Point Depression**: In winter conditions, the temperature can drop significantly. Water, which has a freezing point of 0°C, can freeze in the radiator. Ethylene glycol has a much lower freezing point of approximately -12.9°C. By mixing ethylene glycol with water, the overall freezing point of the coolant mixture is lowered, preventing it from freezing and blocking the engine.

3. **Boiling Point Elevation**: In summer or under high-temperature conditions, the engine can overheat, causing the water in the radiator to boil. Water boils at 100°C, but when mixed with ethylene glycol, the boiling point of the mixture increases to about 197°C. This means that the coolant can withstand higher temperatures without boiling, thus protecting the engine from overheating.

4. **Conclusion**: The dual action of ethylene glycol in lowering the freezing point and raising the boiling point makes it an essential component in vehicle radiators. It ensures that the engine operates efficiently across a wide range of temperatures.

5. **Correct Answer**: The correct role of ethylene glycol in the radiator of vehicles is to decrease the freezing point of water and increase the boiling point of water.