Some acids burn because they have a strong tendency to absorb water, giving out a great deal of heat in the process. Since most living cells contain water the strong acids, react with them and kill the cells, causing very serious burns.
These three acids, as well as others such as perchloric acid and benzine sulphuric acid are called mineral acids because they are manufactured from minerals. They are also strong and dangerous acids. They have tremendous industrial value, but great care must be used in handling them.
Most organic acids-that is to say, those made from living things-are weak acids. Vinegar or lemon juice are examples. All acids taste sour and most attack metals, turning them into salts and releasing hydrogen.
Special clothing is worn by men handling acids to protect them from serious burns. Acid must always be poured slowly into water, never water into acid. If you are burned by acid you should wash your skin with large quantities of water and then with a weak ammonia solution. If your eyes are affected, flush them immediately with lots of water and then with bicarbonate of soda solution, which neutralizes any acid left.