What turns blue litmus paper red?

Answer by  Cjc (299)

Acids turn blue litmus paper red. Common items like citric acid (lemon juice) and acetic acid (vinegar) can be found in almost every household.

Answer by  anrimala36 (208)

An acid (pH of less than 7) will turn blue litmus paper red. Stronger acids (HCl, H2SO4, HNO3, etc.) will show this better since poor quality litmus paper may not be able to distinguish weak bases/acids within a certain range of neutral (ph of 7).

Answer by  IloveScience (118)

Litmus test You need a blue litmus paper and an acidic solution, a non acidic solution. When you put it into a non-acidic solution, it won't turn red. But, if you put it into an acidic solution, it will turn red. It is because acid & alkali depands on concentration of hydrogen ion. It tests the concentration of hydrofen ion.