Red Seal Boilermaker Practice Exam

What is a boiling point elevation phenomenon?

1. An increase in pressure causing boiling point to rise

2. An increase in the boiling point of a liquid due to the presence of additional substances

3. A decrease in the freezing point of a substance

4. A temperature at which a liquid begins to bubble

The correct answer is: An increase in the boiling point of a liquid due to the presence of additional substances

The boiling point elevation phenomenon refers to the increase in the boiling point of a liquid that occurs when a non-volatile solute is added to it. This effect is a colligative property, which means it depends on the number of solute particles in a solution rather than the nature of the solute itself. When a solute is dissolved in a solvent, the solute particles interfere with the ability of the solvent molecules to escape into the vapor phase, which is necessary for boiling to occur. As a result, a higher temperature is required to achieve the vapor pressure needed for the liquid to boil, thus raising the boiling point. This principle is significant in various applications, including cooking and industrial processes, where precise temperature controls are crucial. Understanding boiling point elevation is important for boilermakers as it can impact the operation of systems that involve boiling liquids, such as in heat exchangers or pressure vessels.