Take about 30 ml of vegetable oil in a beaker. Then add 60 ml of 20% sodium hydroxide solution to it.This mixture is heated slowly till it boils. After the mixture has boiled for five to ten minutes add 5grams of sodium chloride in order to separate soap from the solution. Allow the solution to cool. The creamy layer floating on top of the solution is the soap.  Thus soap is prepared by hydrolysing fat or oil with bases such as sodium hydroxide or potassium hydroxide. This process of soap preparation is known as saponification Generally soaps are prepared by heating animal fat or oil with alkalies like sodium hydroxide or potassium hydroxide. This is saponification reaction.Fat or Oil + Alkali → Soap + Glycerol

Preparation of Soap in Laboratory
1. Materials Required
- Coconut oil
- Sodium hydroxide (caustic soda)
- Distilled water
- Beakers
- Thermometer
- Stirring rod
- Bunsen burner
2. Saponification Process
- Mix a measured amount of coconut oil with sodium hydroxide solution in a beaker.
- Heat the mixture gently while stirring continuously.
- Maintain a constant temperature and stir until the mixture thickens and reaches trace, where a drop of the mixture leaves a trail on the surface.
- This process is called saponification, where the fats in the oil react with the sodium hydroxide to form soap and glycerol.
3. Separation of Soap
- After saponification, pour the mixture into a mold and let it cool and solidify.
- Cut the solidified soap into bars or desired shapes.
4. Washing and Drying
- After the soap has solidified, wash it with distilled water to remove any excess sodium hydroxide.
- Allow the soap bars to dry and cure for a few weeks before using them.
5. Testing
- Test the soap for pH level to ensure it is safe for use on the skin.
- You can also add fragrances or essential oils during the soap-making process for a pleasant scent.
By following these steps, you can prepare soap in a laboratory setting using simple ingredients and equipment. Experiment with different oils and additives to create unique and personalized soaps.