Advanced Placement (AP) Chemistry Practice Exam

What is the purpose of distillation in chemistry?

1. To separate substances based on their boiling points

2. To measure the concentration of solutions

3. To neutralize acids and bases

4. To create a homogeneous mixture

The correct answer is: To separate substances based on their boiling points

The purpose of distillation in chemistry is to separate substances based on their boiling points. This technique relies on the principle that different substances will vaporize at different temperatures. When a mixture is heated, the component with the lower boiling point will vaporize first. The vapor is then collected and condensed back into liquid form, allowing for the separation of that component from the original mixture. This method is particularly useful in purifying liquids or separating components in a liquid mixture. For example, in the distillation of crude oil, various hydrocarbons are separated according to their boiling points, producing gasoline, diesel, and other products. The specificity of boiling points allows for effective separation, making this process invaluable in both laboratory and industrial applications. Other options presented don't pertain to the role of distillation. While measuring concentration, neutralizing acids and bases, and creating homogeneous mixtures are important processes in chemistry, they don't involve the separation of substances based on their boiling points, which is the hallmark of distillation.