PIMSO 2025 - Science - Primary 2 - National Round Question 8

Distillation is a process used to purify liquids such as water. A diagram is shown below. In the first stage of the process (labeled A), the liquid is heated to a temperature that will transform it to the gas phase. Then, in the second stage (B), the gas is trapped and allowed to cool down to return it to the liquid phase. What process does the heating do to the liquid in the first stage?



Adapted from Theresa Knott; derivative work John Kershaw. CC BY-SA 3.0. https://commons.wikimedia.org/w/index.php?curid=4219544