Equivalent (chemistry)

In chemistry, an equivalent is a measure of how much of a substance is needed to react with or produce one mole of another substance.

The equivalent mass of a compound is the mass of one equivalent. Unlike molar mass, which is a property of a compound, equivalent mass of a compound depends on the reaction being used as a reference.

 Example 
The Arrhenius acid-base theory treats acids and bases as equivalents of the hydrogen and hydroxide ions. The table shows the acid-base reactions of two different bases and three different acids:



One  and one  make one , so we say that hydrochloric acid is one equivalent of acid and sodium hydroxide is one equivalent of base. When  reacts with , twice as much acid is used to produce twice as much water:  is two equivalents of base. One unit of phosphoric acid makes three units of water,  has three equivalents of acid.

 References 

Category:Chemistry