Question

How many moles of sodium hydroxide are needed to neutralize 1 mole of phosphoric acid?

Answer 1

Hint: Determine the yield means we have to determine the amount of the substance. In a chemical reaction, the yield is determined by using the stoichiometry between the reactants and the products.Stoichiometry is nothing but the mole ratio of reactants and products involved in the balanced chemical reaction. Here, the mole ratio is typically the ratio of integer numbers. In many chemical reactions, the stoichiometric relation is used to determine the amount that is the yield of the product.

Complete solution:
Here, we can write the reaction between the phosphoric acid and the sodium hydroxide is as follows:
${\text{NaOH}}\,{\text{ + }}\,{{\text{H}}_3}{\text{P}}{{\text{O}}_4}\, \to {\text{N}}{{\text{a}}_{\text{3}}}{\text{P}}{{\text{O}}_4}\,{\text{ + }}\,{{\text{H}}_{\text{2}}}{\text{O}}$
It is a neutralization reaction in which base sodium hydroxide reacts with phosphoric acid and produces salt sodium phosphate that is salt and water.
The balanced chemical reaction is as follows:
${\text{3NaOH}}\,{\text{ + }}\,{{\text{H}}_3}{\text{P}}{{\text{O}}_4}\, \to {\text{N}}{{\text{a}}_{\text{3}}}{\text{P}}{{\text{O}}_4}\,{\text{ + 3}}\,{{\text{H}}_{\text{2}}}{\text{O}}$
The mole ratio between the reactants and products is as follows:
${\text{NaOH}}\,\,:\,\,{{\text{H}}_3}{\text{P}}{{\text{O}}_4}\,\,:\,\,{\text{N}}{{\text{a}}_{\text{3}}}{\text{P}}{{\text{O}}_4}\,\,{\text{:}}\,\,\,{{\text{H}}_{\text{2}}}{\text{O}}$
\[{\text{3}}\,\,{\text{mol}}\,\,:\,\,1\,\,{\text{mol}}\,\,{\text{:}}\,\,1\,\,{\text{mol}}\,\,{\text{:}}\,\,3\,{\text{mol}}\]
The stoichiometric mole ratio indicates 3 moles of sodium hydroxide are required to neutralize one mole of phosphoric acid.
${\text{NaOH}}\,\,:\,\,{{\text{H}}_3}{\text{P}}{{\text{O}}_4}$
\[3\,{\text{mol}}\,{\text{:}}\,1\,\,{\text{mol}}\]

Therefore, three moles of sodium hydroxide are needed to neutralize 1 mole of phosphoric acid.

Note:The mole ratio obtained from the balanced chemical reaction is very useful to determine the amount of the species in the reaction.We can determine the amount of the product formed in the reaction or the amount of the reactant required to produce a specific amount of the products.
Here, the given reaction is a balanced chemical reaction hence, use its mole ratio for determining the moles of the hydrochloric acid.The neutralization reaction is the reaction in which acid and base react to give salt and water.