Question

How many grams of $N{a_2}O$ are required to produce $1.60 \times {10^2}$ grams of $NaOH$? $N{a_2}O + {H_2}O \to 2NaOH$

Answer 1

The answer to the question lies on the mole concept. For this we need a balanced chemical equation to know the exact stoichiometry of the reacting substrates.

Complete step by step answer: The given reaction is a hydration reaction for the generation of sodium hydroxide. The reaction is achieved by the treatment of sodium oxide with water.
Sodium oxide is one of the alkali metal oxides which are very strong basic oxide. The basic character of sodium oxide is due to the presence of the oxide ion, ${O^{2 - }}$. The oxide ion has a strong tendency to combine with hydrogen ions and hence serves as a very strong base.
The hydrogen ion sources are water or acids. The reaction of sodium oxide and water is highly exothermic and results in the formation of sodium hydroxide solution. The pH of a concentrated solution of sodium oxide in water is $14$. The reaction is written as
$N{a_2}O + {H_2}O \to 2NaOH$
The above reaction is a balanced chemical equation which describes that one mole of sodium oxide reacts with one mole of water and gives two moles of sodium hydroxide.
The molar mass of $N{a_2}O$ = $2{\text{ }} \times$ atomic mass of $Na$ + atomic mass of $O$
$= 2 \times 23 + 16 = 62g/mol$.
The molar mass of $NaOH$ = atomic mass of $Na$ + atomic mass of $O$ + atomic mass of $H$
$= 23 + 16 + 1 = 40g/mol.$
The stoichiometry between $N{a_2}O$ and $NaOH$ is $1:2$. Thus $62g$ of $N{a_2}O$ on reaction gives $2 \times 40 = 80g$ of $NaOH$.
$1g$ of $NaOH$ is obtained required $\dfrac{{62}}{{80}}g$ of $N{a_2}O$.
Hence for $1.60 \times {10^2}$ grams of $NaOH$, the amount of $N{a_2}O$ required is = $\dfrac{{62}}{{80}} \times 1.6 \times {10^2} = 124g.$

Note:
The basicity of sodium oxide is also observed by the vigorous reaction with acids. Sodium oxide reacts with hydrochloric acid and produces sodium chloride solution. The mole concept is very helpful for determination of exact amounts of reactants taking part in reaction and the exact amount of products formed.