Question

Suggest an explanation for the observations that ethanol, C2H5OH, is completely miscible with water and that ethanethiol, C2H5SH, is soluble only to the extent of 1.5 g per 100 mL of water. ?

Answer 1

Explanation:

Ethanethiol is an organosulphur compound which had an alkyl group(CnH2n+1) and a -thiol group (-SH). A thiol group like an hydroxyl group has its Oxygen replaced with sulphur.

Ethanethiol shows little association of its -SH group with the water molecules by hydrogen bonding; both with water molecules and among themselves. Hence why they are less soluble in water or slightly soluble in water.

Ethanol is an organic compound which the general formula of CnH2n+1OH. Ethanol is soluble in water because of the reaction of the -OH group with the water molecules to form hydrogen bonds.

Note that as the alkyl chain increases, Solubility decreases. This is because the alkyl chain forms the hydrophobic surface of the molecule due to its non-interaction of the water molecules to form hydrogen bond.