Neutral compounds are chemical mixtures that don't react with acid or base chemicals. Neutral compounds have no electrical charge, so they do not absorb ions from other chemicals. On a pH scale, a liquid that has a reading of exactly seven is a neutral substance.
Litmus paper is used to test the pH of a chemical. Acids turn blue litmus paper red and show a pH of less than seven. The lower the number of the reading, the more acidic. Alkaline fluids are base mixtures that accept ions and read more than seven on litmus paper. The higher the number, the greater the alkalinity.