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.
A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value. For example, pH 4 is ten times more acidic than pH 5 and 100 times (10 times 10) more acidic than pH 6. The same holds true for pH values above 7, each of which is ten times more alkaline (another way to say basic) than the next lower whole value. For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times 10) more alkaline than pH 8. Pure water is neutral. But when chemicals are mixed with water, the mixture can become either acidic or basic. Examples of acidic substances are vinegar and lemon juice.