Organic Chemistry MCAT Practice Exam

What occurs in a separatory funnel when separating liquids of different polarities?

1. Aqueous layer contains amines and alcohols

2. Organic layer contains carboxylic acids

3. Aqueous layer contains compounds to be extracted

4. Organic layer contains non-polar compounds

The correct answer is: Aqueous layer contains compounds to be extracted

In a separatory funnel, when separating liquids of different polarities, the organic layer typically contains non-polar or less polar compounds, while the aqueous layer contains more polar compounds. The principle behind this separation is based on differences in polarity. The correct response highlights that the aqueous layer contains compounds that can be extracted, which usually are more polar substances. Polar compounds tend to dissolve well in water, allowing them to be present in the aqueous layer. This includes substances such as salts, sugars, and some acids that have polar functional groups. In contrast, non-polar compounds, which do not interact well with water, will preferentially dissolve in the organic layer, where they remain separated from the polar aqueous phase. This distinction in solubility is crucial for the effective separation of compounds based on their polarity. Understanding this concept is essential for performing liquid-liquid extractions efficiently in an organic chemistry context.