Reaction of alcohols with sodium

Exercise 3

A saturated aliphatic monoalcohol $A$ reacts with an excess of sodium. A salt is obtained which contains $23.96 \;\%$ sodium 1) Write the equation of this reaction using the general formulas. 2) Determine the molecular formula of alcohol $A$. 3) Knowing that $A$ is optically active, represent the stuctural formula of its $S$ enantiomer!

1) Equation: $C_nH_{2n+2}O$ $+$ $Na$ $\rightarrow$ $ C_nH_{2n+1}ONa$ $+$ $\frac{1}{2}H_2$ 2) Percentage of $Na$: $\frac{23\cdot 100}{12n+2n+1+16+23}$ $=$ $23.96$ $n\;=\;4$ Molecular formula of $A$: $C_4H_{10}O$ 2) ($S$)-butan-2-ol