One of the most traditional experiments in the study of chemistry is to make soap from an oily material or oil. In this article, we will look at how to make homemade liquid soap, from simple materials quickly and effectively, using reaction concepts based on organic chemistry.
- A recent glass.
- A mixing paddle or wooden spoon.
- Caustic soda.
Procedure for making liquid soap
The procedure for making liquid soap is quite simple. We start by thoroughly washing our container with a dishwasher. Then, we dry it and add about 3 litres of water.
With the water in the container, carefully add about 500 g of caustic soda little by little. Keep in mind that this reaction is exothermic and that heat energy is released, so add the caustic soda very slowly and in small portions and mix with the water until it dissolves. Important note: Remember to protect your hands with gloves and avoid skin contact, preferably wear protective glasses and a lab coat.
Once we have the caustic solution, we add little by little about 3 litres of oil, while mixing with a wooden spoon. This procedure is very slow and must be prolonged for at least an hour for the mixing to be perfect and for the reaction to take place completely. If we do it well, we will see a thick paste of a very light colour, almost whitish.
This mixture is our raw soap, let it stand for at least two days and it will be ready for use. It is advisable to use indicator paper to verify that its PH is not high (the PH of the soap should not be higher than 8), if so, we must reduce the amount of caustic soda and carry out the process again.
If we wish to add colour and smell, we can use colourants and essences in the mixture.
How soap is created
Soap is the result of a reversible reaction, which is called saponification. In this reaction, an alkaline solution reacts with a triglyceride (oil) to generate a polar salt and water. This salt is the soap that reacts to form foam, which removes the dirt thanks to another electrochemical reaction, which takes place on the surface to be cleaned.