Which liquid is collected in the test tube of a fractional distillation?

In fractional distillation, the liquid collected in the test tube is typically the condensed vapor of the component with the lowest boiling point from a mixture. As the mixture is heated, different components vaporize at different temperatures, and the vapor rises through the fractional column. The vapor then condenses and is collected as a liquid in the test tube, allowing for the separation of the components based on their boiling points.