Discussion on the Equivalence of Phosphoric Acid The equivalent of
phosphoric acid ($H_3PO_3 $) is a key consideration in real chemistry. Equivalent is the amount involved in the specific proportional relationship of substance interactions in chemical reactions. The structure of

phosphoric acid has its own uniqueness. Although the molecular formula is $H_3PO_3 $, only two hydrogen atoms can be dissociated in general acid and base reactions, resulting in acidity. This is because in the phosphoric acid structure, a hydrogen atom is directly connected to the phosphorus atom, which is difficult to ionize.

Based on this, the calculation of the equivalent of phosphoric acid depends on the number of hydrogen ions involved in the reaction. In cases such as acid-base neutralization, phosphoric acid can provide two hydrogen ions to participate in the reaction.

Generally speaking, the equivalent of an acid is calculated by dividing its molar mass by the number of hydrogen ions participating in the reaction. The molar mass of phosphite is about $82g/mol $ ($H $: $1g/mol $, $P $: $31g/mol $, $O $: $16g/mol $, 3 dollars\ times1 + 31 + 3\ times16 = 82 $). Since it can provide two hydrogen ions to participate in the reaction, the equivalent is the molar mass divided by 2 dollars $, which is 82 dollars\ div2 = 41g/equiv $.

In summary, the equivalent of phosphite is $41 g/equiv $, which is of great significance in many aspects related to the chemical reaction metrology analysis and solution concentration allocation of phosphite.