1) Take about 20 ml of vegetable oil in a beaker.
2) Then, add 30 ml of 20% sodium hydroxide solution to it.
3) This mixture is heated slowly till it boils.
4) Then add 5 to 10 grams of sodium chloride (common salt).
5) Stir the mixture well and allow it to cool. On cooling the solution, solid soap separates out. 6. When the soap sets, it can be cut into pieces called 'soap bars'.
This process of soap preparation is known as saponification.