Question

In the second paragraph discuss briefly how adjusting pH of the aqueous phase as a means of altering solubility properties of compounds is used in extractions.

Answer 1

The fundamental theory behind this technique is that salts, which are ionic, tend to be water-soluble while neutral molecules tend not to be.

The addition of an acid to a mixture of an organic base and acid will result in the acid remaining uncharged, while the base will be protonated to form a salt. If the organic acid, such as a carboxylic acid, is sufficiently strong, its self-ionization can be suppressed by the added acid.

Conversely, the addition of a base to a mixture of an organic acid and base will result in the base remaining uncharged, while the acid is deprotonated to give the corresponding salt. Once again, the self-ionization of a strong base is suppressed by the added base.