Question

What is the mole ratio of `H_2O` to `H_3PO_4` in the following chemical equation? `P_4O_10 + 6H_2O -> 4H_3PO_4`?

Answer 1

Well the stoichiometry demands 6 equiv of water per 1 equiv water.

Explanation:

And so the molar ration is `6:1`, `"water:phosphoric acid"`.......

And you have written the stoichiometrically balanced chemical reaction to inform you.

Note that `P_4O_10` is a common laboratory reagent for drying halogenated reagents such as methylene chloride. Because `P_4O_10` reacts with atmospheric water, often when you open a used bottle of phosphorus pentoxide, you see a sticky white syrup on the surface of the reagent, where atmospheric water has reacted with the oxide. When you dig down, sometimes you find the actual reagent, which should be a free-flowing powder.