What is the effect of mixing soap and washing powder?
In our daily life, we often hear people say that after washing clothes with washing powder, if the clothes are easily dirty, such as the mouth, if they are washed with soap, their decontamination ability will be reduced. Because washing powder is acidic, soap is alkaline, and its detergency will of course be reduced in acid-base neutralization. It sounds quite scientific, but it is actually a misunderstanding.
We know that the main ingredient of soap is the sodium salt of higher fatty acid, and there are also fillers such as flavor, bactericide, active agent, etc. In the production process, strong alkali needs to be added, as well as its own hydrolysis:
RCOO-＋H 2O≒RCOOH ＋OH-
Therefore, the solution is alkaline when used, and the soap is generally less alkaline because it is neutralized by adding acid during production. There are many types of synthetic detergents, which can be divided into three types according to their structure: anionic, cationic and non-ionic. Among them, the washing powder widely used in daily life is anionic.
Due to the addition of strong alkali and its own hydrolysis during neutralization, the shampoo and body wash used in daily life are mostly non-ionic, neither ionized nor hydrolyzed in water, so the aqueous solution is neutral. Only cationic detergents were hydrolyzed in aqueous solution and showed weak acidity, but their hydrophilic and hydrophobic groups did not react with soap, so the activity of the groups did not decrease. Therefore, in daily life, when you are doing laundry or bathing, you don't need to be so jealous. While enjoying the pleasure of cleaning, you might as well add a touch of fragrance to add color to your life.