Question

A student has a flask containing two immiscible liquids. One of the liquids is a solution of a solid in water. Describe how you would separate the mixture into three separate components.

Answer 1

The mixture can be separated into three separate components by using a centrifuge and a separating funnel.

A centrifuge is used to separate a solid that is held in suspension by a liquid. In this case a solid dissolved in water. In contrast, a separating funnel is used to separate two immiscible liquids.

-First take the flask containing the two immiscible liquids and pour contents in to a closed separating funnel.

- The most dense liquid will settle at the bottom, then open the separating funnel valve to collect contents of dense liquid into a flask.

- The remaining liquid on the separating funnel can be collected in a different flask.

-Now take the liquid that is a solution of a solid in water and pour in a test tube. Place the contents in a centrifuge.

- Centrifuge at high speed until the solid sinks to the bottom of the test tube, then decant the liquid into a flask and the solid remains in the test tube

Answer 2

Answer:

It can be separated using a separating funnel followed by crystallization.

Explanation:

First the mixture is put into a separating funnel. This will separate the two immiscible liquids. When the two immiscible liquids are separated, we recall that one is a solution of a solid solute and we wish to recover the solid from the solution whilst recovering the solvent also.

The solid can only be recovered by crystalization if we do not want to loose the solvent. Seeds of already crystalized solute may be added to system to induce crystalization.