Question

Sodium ethoxide is prepared by the reaction of ethanol with aqueous sodium hydroxide.
A) True
B) False

Answer 1

Hint: To solve this we must know that sodium ethoxide has molecular formula ${{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{ONa}}$. We must know the products of the reaction when ethanol i.e ethyl alcohol reacts with sodium hydroxide. The molecular formula of ethanol is ${{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{OH}}$ and that of sodium hydroxide is ${\text{NaOH}}$.

Complete answer:
We know that sodium ethoxide has molecular formula ${{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{ONa}}$. Sodium ethoxide is colourless in appearance.
When ethanol $\left( {{{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{OH}}} \right)$ is added to aqueous sodium hydroxide $\left( {{\text{NaOH}}} \right)$, no reaction occurs. This is because aqueous sodium hydroxide contains sodium ions $\left( {{\text{N}}{{\text{a}}^ + }} \right)$ and hydroxide ions $\left( {{\text{O}}{{\text{H}}^ - }} \right)$. In aqueous solution, the sodium ions $\left( {{\text{N}}{{\text{a}}^ + }} \right)$ and hydroxide ions $\left( {{\text{O}}{{\text{H}}^ - }} \right)$ are mobile and thus, ethanol cannot react with the sodium ions to form sodium ethoxide. Thus, we can say that ethanol does not react with aqueous sodium hydroxide.

Sodium ethoxide is prepared by the reaction of ethanol with sodium metal $\left( {{\text{Na}}} \right)$. The reaction of ethanol with sodium metal is as follows:
${\text{2}}{{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{OH}} + 2{\text{Na}} \to 2{{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{ONa}} + {{\text{H}}_2}$
The by-product of the reaction is hydrogen gas. During the reaction, bubbles of hydrogen gas can be observed.

The reaction of ethanol with sodium metal is an acid-base reaction. The reaction helps to show the acidic nature of ethanol. Thus, sodium ethoxide is prepared by the reaction of ethanol with sodium metal.
Thus, the statement ‘sodium ethoxide is prepared by the reaction of ethanol with aqueous sodium hydroxide’ is false.

Thus, the correct option is (B) false.

Note: Ethanol is a very toxic solvent. It is colourless in appearance, has a faint odour and is highly flammable. Ethanol is used as a psychoactive drug. It is an active ingredient in alcoholic beverages. Sodium is a free metal and it does not exist in nature because of its high reactivity.