Question

$NaOH$ is formed according to the following reaction:
$2Na+\frac{1}{2}{O}_2⟶Na{O}_2$
$N{a}_{2}O+H_{2}O⟶2NaOH$
To make $4$ g $NaOH$, $Na$ required is :

• A. $4.6$ g
• B. $4.0$ g
• C. $2.3$ g
• D. $0.23$ g

Answer 1

The correct option is C $2.3$ g

The reactions are as follows:
$2Na+\frac{1}{2}{O}_2⟶N{a}_{2}O$
$N{a}_{2}O+H_{2}O⟶2NaOH$
According to the balanced reaction, $2$ moles of $NaOH$ require $2$ moles of $Na$.
Therefore, $4$ g ($0.1$ mol) $NaOH$ requrie $0.1$ mol $Na$, i.e. $23\times 0.1=2.3$ g of $Na$.