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Does Antifreeze Raise Boiling Point of Water? (Explained)

Antifreeze, also known as coolant, is a liquid mixture used in internal combustion engines and other heat transfer applications to lower the freezing point and raise the boiling point of water.


The most common antifreeze is a 50/50 mixture of water and ethylene glycol, although different formulations exist with varying ratios of water to antifreeze.


In this article, we will explain if antifreeze raises the boiling point of water and if it reduces the freezing point of water.

 

Table of Contents:


antifreeze being poured into a car coolant reservoir

How Does Antifreeze Work?

Antifreeze works by lowering the freezing point of water, which prevents the liquid from turning into ice at low temperatures. This is important for internal combustion engines, as ice can expand and cause damage to the engine, it can also cause the engine to seize up.


Antifreeze also raises the boiling point of water, which helps to prevent overheating in the engine.


Does Antifreeze Raise Boiling Point of Water?

Yes, antifreeze raises the boiling point of water. Specifically, a 50/50 mixture of water and ethylene glycol raises the boiling point of water from 212°F (100°C) to 223°F (106°C).


Additionally, a 30/70 mixture of water and ethylene glycol raises the boiling point to an even higher temperature of 235°F (113°C).


Boiling and Freezing Point of Coolant vs Water

  • Pure Water: The boiling point of pure water is 212°F (100°C) and it has a freezing point of 32°F (0°C) at sea level.

  • 50/50 Mixture of Water and Ethylene Glycol (Anti-freeze): A 50/50 mixture of water and ethylene glycol raises the boiling point to 223°F (106°C) and lowers the freezing point to -35°F (-37°C) at sea level.

  • 30/70 Mixture of Water and Ethylene Glycol (Anti-freeze): A 30/70 mixture of water and ethylene glycol raises the boiling point to 235°F (113°C) and reduces the freezing point to -67°F (-55°C) at sea level.


Why Does Anti-freeze Raise Boiling Point and Reduce Freezing Temperature?

Anti-freeze, also known as engine coolant, raises the boiling point and reduces the freezing temperature of the liquid in which it is dissolved. This is due to the fact that anti-freeze is a type of chemical called an "inhibitor".


Inhibitors work by altering the properties of a liquid so that it can withstand higher temperatures and colder temperatures without boiling or freezing. In the case of anti-freeze, the active ingredient is typically ethylene glycol or propylene glycol.


These compounds lower the freezing point and raise the boiling point of the liquid in which they are dissolved by inhibiting the formation of ice crystals and preventing the liquid from boiling.


The presence of ethylene glycol or propylene glycol molecules in the liquid creates a "hindrance" to the formation of the orderly crystal lattice of ice or boil, effectively slowing it down and thereby increasing the temperature where freezing or boiling takes place.


It's important to note that anti-freeze is toxic for humans, pets and wildlife and it's crucial that any accidental spillage or leakage is cleaned up properly.


Does Antifreeze Prevent Water From Boiling?

No, antifreeze does not prevent water from boiling. It raises the boiling point of water, which means that it takes a higher temperature for the liquid to reach its boiling point.


However, when the temperature reaches the raised boiling point, the liquid will still boil, and a pressure relief mechanism needs to be in place to release the steam generated.


Conclusion

Antifreeze is a liquid mixture used to lower the freezing point and raise the boiling point of water, which is essential for maintaining the proper function of internal combustion engines and other heat transfer applications.


The addition of antifreeze, typically in the form of ethylene glycol, raises the boiling point of water, making it more difficult for the liquid to boil. However, when the temperature does reach the raised boiling point, the liquid will still boil.


It's important to note that increasing the boiling point of water doesn't prevent the liquid from boiling completely.

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