This is a chemical, usually a liquid, that contains hydrogen and has a pH of less than seven
acid
This is a a chemical substance that reacts with acids to form a salt and gives a solution with a pH of more than seven when it is dissolved (= mixed with a liquid and becoming part of it) in water
Alkali
This word means to slowly destroy or damage metal, stone or other materials by chemical action; to be destroyed in this way
Corrode