Updated: Feb 2
✔ This article has been fact checked.
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.
Yes, antifreeze raises the boiling point of water, it prevents the coolant from boiling over when the engine runs hot. The more ethylene glycol that is added, the higher the boiling point is, a 50:50 antifreeze mixture raises the boiling point to 106℃ (223℉).
In this article, we will explain how antifreeze raises the boiling point of water and if it reduces the freezing point of water.
Table of Contents:
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 the water in the coolant mixture from boiling over.
How Antifreeze Raise Boiling Point of Water?
The boiling point of a substance is determined by the strength of the intermolecular forces between its molecules. Antifreeze raises the boiling point of water by increasing the energy it takes to pull the molecules apart.
Ethylene glycol, the main substance in antifreeze, has a higher boiling point than similarly sized hydrocarbons because its molecules are attracted to each other through opposite charges.
This attractive force can be thought of as "molecular Velcro", making it more difficult to separate the molecules and increasing the energy required to boil the liquid. The stronger the intermolecular forces, the higher the boiling point.
Boiling and Freezing Point of Coolant vs Water
Pure water has a different boiling and freezing point than when antifreeze is added, the more ethylene glycol that is added, the lower the freezing point and the higher the boiling point.
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 antifreeze: 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 antifreeze: 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 Antifreeze 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 of the liquid in which they are dissolved in by inhibiting the formation of ice crystals.
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, effectively slowing it down and thereby increasing the temperature where freezing 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.
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.
Wikipedia. "Antifreeze" https://en.wikipedia.org/wiki/Antifreeze
Wikipedia. "Ethylene Glycol" https://en.wikipedia.org/wiki/Ethylene_glycol