Bleach ingredients

People may rarely come into contact with bleach in their daily lives, but in fact this substance is widely used. It is mainly produced by the reaction of water and chemical substances. It is usually used in industry, but a small number of them are also used to bleach clothes, especially when your clothes turn yellow after being worn for a long time, you can use bleach at this time.

Bleach is a newly prepared aqueous solution of bleaching powder, and its composition is Ca(ClO)2+CaCl2·Ca(OH)2·H2O+H2O. The main components of bleaching powder are calcium hypochlorite and calcium chloride. Calcium hypochlorite is the active ingredient. Calcium hypochlorite can react reversibly with water to generate hypochlorous acid (with strong oxidizing properties), reduce colored substances and achieve the purpose of bleaching.

In industry, there is the concept of bleach, and different bleaches have different uses. In daily life, some people often call bleach "bleaching water".

Bleach has a wide range of uses. In industry, dyeing and bleaching factories use the most. A large family also always has bleach on hand to bleach some yellowed clothes. When bleaching colored clothes, it is best to use bleach that is not easily discolored. Bleach is not the same as bleaching powder. Using bleaching powder alone to bleach clothes will not have any bleaching effect.

When doing the experiment, you can put some bleaching powder in a test tube, add five times the same weight of water, and then take a small piece of colored cloth and dip it into the test tube. You can observe that the color of the cloth does not change, which proves that bleaching powder itself has no bleaching ability. If you add a few drops of dilute sulfuric acid or hydrochloric acid, the color on the cloth will disappear and the cloth has been bleached. Why does adding sulfuric acid to bleaching powder produce a bleaching effect? Because bleaching powder is made of quicklime and chlorine, it produces hypochlorous acid when it comes into contact with dilute sulfuric acid or hydrochloric acid; it is this "hypochlorous acid" that can perform the bleaching effect.

Although it is simple to make bleaching water by adding bleaching powder to dilute sulfuric acid or hydrochloric acid, it is not economical. The best and most economical method is to use electrolysis of salt to produce sodium hypochlorite, which is an ideal and cheap bleach.

Table salt is sodium chloride. Sodium chloride can be decomposed using electricity until its cathode completely turns into soda ash and its cathode completely turns into chlorine gas. Sodium hypochlorite is a mixture of these two things.

Dry chlorine gas has no bleaching effect. It must be in the presence of moisture. Chlorine gradually changes with water to produce hypochlorous acid and hydrochloric acid. Hypochlorous acid then decomposes into nascent oxygen. This "nascent oxygen" has bleaching ability. Primary oxygen (O) is oxygen that has not yet polymerized into molecules. It can not only bleach, but also kill bacteria, so "chlorine water" is also a kind of bleach.