Question

Explain why soaps are more soluble in water that fatty acids in water

Answer 1

Fatty acids consist of long hydrophobic chains and at the terminal they have carboxylic group (-COOH). This long chain is consist aliphatic carbons and at some position they consist double bonds (unsaturated). Here long fatty acids cannot make hydrogen bond with water hence fat is not soluble. They aggregate on the surface of water.

On the contrary to that, soaps are made up of sodium/potassium salts of fatty acids. The reaction of sopnification is

Fat + NaOH -----à Na salt of fatty acid + glycerol.

Once the soap comes in contact with water then sodium slat will break down and make and hydrophilic end that makes hydrogen bond with water these polar heads are situated outside and hydrophibic ends gather at the center. It make micelle in water. That’s why soap is soluble in water.