Acid vs. Base

Acids and bases are two classifications of chemical substances, as determined by the pH scale, with the classification of neutral falling in between.

An acid is a chemical substance that measures less than 7 on the pH scale. They tend to be sour and can be quite hazardous. Acids turn blue litmus paper (an indicator of pH level) red and react with bases to form salt. Weaker acids, like vinegar, have pH levels closer to 7. Stronger acids, like battery acid, have pH levels closer to 1 and can be very dangerous.

A base is a chemical substance that measures greater than 7 on the pH scale. They are generally bitter and feel slippery. Bases turn red litmus paper (an indicator of pH level) blue and react with acids to form salt. Weaker bases, like soap, have pH levels closer to 7. Stronger bases, like drain cleaner, have pH levels closer to 14 and can be dangerous.

Acids and bases are measured on the pH scale, which determines how acidic or basic an aqueous substance is. Water, with a pH of 7, is considered neutral.