Which one of the following is used in the manufacture of soaps?

Correct answer: (a) Vegetable oil

Explanation

Soap is made by saponification: a vegetable oil or animal fat is boiled with sodium hydroxide (or potassium hydroxide for soft soap):

Fat/oil + NaOH → soap (sodium salts of fatty acids) + glycerol

Mobil oil, kerosene and cutting oil are mineral oils (hydrocarbons) and cannot be saponified.