Extraction Techniques in Chemistry

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Questions and Answers

What is the purpose of the separatory funnel?

To measure the volume of a liquid

To separate liquids based on their densities (correct)

To heat a mixture of liquids

To mix liquids together

What happens when you shake the separatory funnel and allow the mixture to settle?

The mixture becomes homogeneous

The mixture becomes more viscous

The mixture separates into two distinct layers (correct)

The mixture evaporates quickly

What is the difference between the organic phase and the aqueous phase?

The organic phase is more dense, while the aqueous phase is less dense

The organic phase is acidic, while the aqueous phase is basic

The organic phase contains neutral compounds, while the aqueous phase contains water and ions (correct)

The organic phase contains water and ions, while the aqueous phase contains neutral compounds

Why do liquids separate into two distinct layers in the separatory funnel?

Because they have different densities Signup and view all the answers

What is the function of the stopcock in the separatory funnel?

To prevent liquid from flowing freely from the separatory funnel to the flask Signup and view all the answers

What is the first step in performing an extraction?

Open the stopcock Signup and view all the answers

What is the purpose of extraction in the perfume industry?

To isolate specific chemical compounds Signup and view all the answers

What is the name of the glassware used in extraction?

Separatory funnel Signup and view all the answers

What is the purpose of adding hydrochloric acid to the mixture of hexane and propanamine?

To protonate the amino group Signup and view all the answers

Why is sodium bicarbonate used in the extraction of acetic acid and phenol from hexane?

Because it is a mild base that can deprotonate acetic acid but not phenol Signup and view all the answers

What happens to the phenol when sodium hydroxide is added to a mixture of hexane, phenol, and acetic acid?

It becomes deprotonated and moves to the aqueous layer Signup and view all the answers

What is the purpose of separating the layers in an extraction process?

To separate the compounds based on their properties Signup and view all the answers

What happens to the propanamine when hydrochloric acid is added to a mixture of hexane and propanamine?

It becomes protonated and moves to the aqueous layer Signup and view all the answers

What is the advantage of using a multi-step extraction process?

It allows for the recovery of products from waste containers Signup and view all the answers

Why is phenol weakly acidic?

Because it has a weak hydroxyl group Signup and view all the answers

What is the purpose of adding a base to a mixture of hexane and phenol?

To deprotonate the phenol Signup and view all the answers

What happens to the acetic acid when sodium bicarbonate is added to a mixture of hexane, acetic acid, and phenol?

It becomes deprotonated and moves to the aqueous layer Signup and view all the answers

Why is it important to save each layer in an extraction process?

Because some layers may contain valuable products Signup and view all the answers

Study Notes

Extraction

Extraction is a technique used to isolate chemical compounds by separating them from a mixture based on their differences in density.
It involves using a separatory funnel (sep funnel) and a flask as main pieces of glassware.

Separatory Funnel (Sep Funnel)

A sep funnel has an opening at the top for pouring in liquid and a stopcock at the bottom that prevents liquid from flowing freely into the flask.
Shaking the sep funnel and allowing the mixture to settle results in two distinct layers: a higher-density layer at the bottom and a lower-density layer on top.

Density and Phases

The higher-density layer at the bottom is often the aqueous phase, which contains water and charged species (ions).
The lower-density layer on top is often the organic phase, which contains uncharged species (neutral compounds).

Extraction Process

To perform an extraction, open the stopcock to allow the aqueous phase to flow into the flask, leaving the organic phase in the sep funnel.
Close the stopcock after collecting the aqueous layer, and repeat the process as needed.

Examples of Compounds and Extraction

Hexane is a neutral compound, while propanamine is basic due to its amino group.
Adding hydrochloric acid (HCl) to a mixture of hexane and propanamine allows the amino group to deprotonate, creating a charged species that separates into the aqueous layer, leaving hexane in the organic layer.
Phenol is weakly acidic and can be extracted into the aqueous layer by adding a strong base like sodium hydroxide (NaOH), leaving hexane in the organic layer.
Adding sodium bicarbonate (a mild base) to a mixture of hexane, phenol, and acetic acid can extract the acetic acid into the aqueous layer, while leaving phenol and hexane in the organic layer.
Adding NaOH to the remaining organic layer can then extract the phenol into the aqueous layer, leaving hexane in the organic layer.

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Description

Learn about the extraction technique used to isolate chemical compounds from a mixture based on their density differences. Understand the role of a separatory funnel and flask in the process.