Definition of common for Students. 1  1 : affecting, belonging to, needed by, or used by everybody for the common good a common room. 2  2 : shared by two or more individuals or by the members of a family or group a common ancestor. 3  3 : 1general 1 common knowledge. 4  4 : occurring, appearing, or used frequently a common sight a common name.
1 Apple cider vinegar is highly acidic. 2  The main ingredient is acetic acid, which is quite harsh. 3  You should always dilute it with water or juice before swallowing. 4  Pure, straight apple cider vinegar could damage your tooth enamel or the tissues of your mouth and throat. Apple cider vinegar is highly acidic. 2  The main ingredient is acetic acid, which is quite harsh. 3  You should always dilute it with water or juice before swallowing. 4  Pure, straight apple cider vinegar could damage your tooth enamel or the tissues of your mouth and throat.
Battery acid is ranked as one of the most acidic substances because is has a pH value of zero. Concentrated sulfuric acid is also very acidic, being listed as one. Lemon juice and vinegar are also very acidic, but not as much so since they are ranked at a level two pH rating. Some other acidic substances are orange juice and soda, which have a pH rating of three.