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

To solve the question regarding the role of ethylene glycol in the radiator of vehicles, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Function of a Radiator**:
- A vehicle's radiator is designed to regulate the engine's temperature by dissipating heat. It uses a coolant to absorb and transfer heat away from the engine.

2. **Identifying the Role of Ethylene Glycol**:
- Ethylene glycol is commonly used as a coolant in vehicle radiators. Its primary functions are to prevent the coolant from freezing in cold temperatures and to raise the boiling point of the coolant in hot conditions.

3. **Freezing Point Depression**:
- In winter, ethylene glycol lowers the freezing point of the coolant mixture. This prevents the coolant from freezing, which could lead to engine damage.

4. **Boiling Point Elevation**:
- In summer or high-temperature conditions, ethylene glycol raises the boiling point of the coolant. This allows the coolant to remain effective at higher temperatures, preventing overheating of the engine.

5. **Conclusion**:
- Therefore, the role of ethylene glycol in the radiator is to both decrease the freezing point in winter and increase the boiling point in summer, ensuring optimal engine performance throughout the year.

### Final Answer:
The role of ethylene glycol in the radiator of vehicles is to decrease the freezing point of the coolant in winter and increase the boiling point in summer.