Unit 2: Separating Techniques of Physical Mixtures Quiz 3

In solvent extraction, what is the primary role of the solvent?

• To chemically react with the mixture
• To dissolve the required component from the mixture
• To filter out the impurities
• To change the temperature of the mixture

Answer explanation

The solvent dissolves the required component without dissolving other components in the mixture.

Which of the following is an example of a solvent used in the extraction of vegetable oils?

• Water
• Ethanol
• Hexane
• Benzene

Answer explanation

Hexane is commonly used as a solvent in the extraction of oils from vegetable materials.

During a solid-liquid extraction, what happens to the target solid component?

• It dissolves in the solvent
• It evaporates
• It remains undissolved and is separated by filtration
• It reacts with the solvent

Answer explanation

The target solid component remains undissolved and is separated by filtration after the mixture is dissolved in the solvent.

In liquid-liquid extraction, which property of the two liquids allows them to be separated?

• Similar boiling points
• Immiscibility
• Same density
• Solubility in each other

Answer explanation

Liquid-liquid extraction relies on the immiscibility of the two liquids, allowing them to form separate layers that can be separated.

Which apparatus is used in solvent extraction to continuously extract a component from a solid?

• Separatory funnel
• Soxhlet extractor
• Distillation column
• Chromatography paper

Answer explanation

A Soxhlet extractor is used for the continuous extraction of a component from a solid using a solvent.

Why is agitation important during solvent extraction?

• To increase the temperature
• To reduce the density of the mixture
• To enhance the transfer of the required component from the mixture to the solvent
• To chemically react with the impurities

Answer explanation

Agitation helps in better mixing and enhances the transfer of the required component to the solvent.

If a student needs to separate a mixture of ethanol and benzene, which property should they consider to select an appropriate solvent?

• Density
• Boiling point
• Solubility
• Color

Answer explanation

Solubility of the components in the solvent is crucial for selecting an appropriate solvent for extraction.

In the extraction of essential oils, why is it important to use a non-toxic solvent?

• To increase the yield
• To ensure the safety and purity of the final product
• To reduce the boiling point
• To enhance the color of the oil

Answer explanation

Using a non-toxic solvent ensures that the extracted essential oils are safe and pure for use.

What is the main advantage of using a Soxhlet extractor in solvent extraction?

• It requires less solvent
• It operates at room temperature
• It allows for continuous extraction without the need to replace the solvent
• It filters the mixture automatically

Answer explanation

The Soxhlet extractor allows for continuous extraction, making the process efficient and minimizing solvent use.

During an experiment, a student uses a solvent that dissolves both the required component and an impurity. What additional step should they take to purify the required component?

• Increase the temperature
• Use a different solvent
• Perform filtration
• Use distillation to separate the dissolved components

Answer explanation

If the solvent dissolves both the required component and an impurity, distillation can be used to separate them based on their boiling points.