# What is the chemical equation for diphosphorus trioxide + water ---> phosphorous acid?

May 13, 2014

Diphosphorus trioxide + water produces phosphorous acid.

Diphosphorous trioxide is a molecular (covalent) compound. Using the prefixes the molecular formula is ${P}_{2} {O}_{3}$

Phosphorous acid is ${H}_{3} P {O}_{3}$

${P}_{2} {O}_{3} + {H}_{2} O \to {H}_{3} P {O}_{3}$

To balance this equation we begin be adding a coefficient of 2 in front of the phosphorous acid.

${P}_{2} {O}_{3} + {H}_{2} O \to 2 {H}_{3} P {O}_{3}$

We balance the hydrogen by adding a coefficient of 3 in front of the water.

${P}_{2} {O}_{3} + 3 {H}_{2} O \to 2 {H}_{3} P {O}_{3}$