Liquid-liquid extractions separate compounds based on which property?
Group of answer choices
Boiling point
Density
Polarity
Solubility
The correct answer and explanation is:
The correct answer is Solubility.
Liquid-liquid extraction is a separation process that relies on differences in the solubility of compounds in two immiscible liquids. Typically, one of the liquids is water (polar), and the other is an organic solvent (nonpolar). The principle behind this technique is that a compound will dissolve in one liquid phase more readily than in the other, allowing it to be selectively transferred from one phase to the other.
The extraction works because different compounds have varying solubility in different solvents. For example, a compound that is more soluble in an organic solvent will move from the aqueous phase into the organic phase when the two liquids are mixed. The solubility difference is often due to the chemical nature of the solvents and the compounds involved. A polar compound will dissolve better in a polar solvent like water, while a nonpolar compound will tend to dissolve in a nonpolar organic solvent.
In practice, liquid-liquid extraction is often used in laboratories and industrial settings to isolate specific compounds from mixtures. For instance, when separating an acidic compound from a neutral one, an acid can be extracted into an aqueous phase by adjusting the pH. Another common application is the extraction of essential oils from plants, where the oil, which is typically nonpolar, will be extracted into an organic solvent, leaving behind water-soluble components.
Factors such as boiling point and density also influence extraction but are not the primary mechanisms for separation in liquid-liquid extraction. Boiling point is more relevant in distillation, and density differences can aid in separating the two phases but do not determine which compounds are extracted. Therefore, solubility is the key property being utilized in liquid-liquid extraction.