How Sugar Helps Water Boil

Water boiling

Boiling is the rapid transition of a liquid to its vapor form. At sea level, water boils at a temperature of 100 degrees Celsius, the equivalent of 212 degrees Fahrenheit. Adding a compound such as sugar to water will increase its boiling temperature.

The Facts

The boiling point of a solution is always higher than the boiling point of a pure solvent. A solution of sugar and water will reach a higher temperature before boiling than water will by itself.

The Science

The vapor pressure of a liquid increases as the liquid is heated, and boiling occurs when the vapor pressure of the liquid becomes equal to the air pressure surrounding it. A compound such as sugar has a vapor pressure of zero. Adding sugar to water decreases the overall vapor pressure of the solution, causing the water to boil at a higher temperature.

Significance

Increasing the boiling point of water means that the water will take longer to boil. The water will also be at a higher temperature when it boils, which means that food will cook faster in it.

References

• Clackamas Community College: Vapor Pressure Change
• Purdue Chemistry Department: Solutions