Question

Name the oxidizing agent used for the conversion of ethanol to ethanoic acid. Distinguish between ethanol and ethanoic acid on the basis of (i) litmus test, (ii) reaction with sodium hydrogen carbonate.

Answer 1

In organic conversion, the reagent reacts with a reactant molecule to produce intermediates that are converted into final products.

Strong oxidizing agent is required for the conversion of an alcohol to an acid. Thus, acidified potassium dichromate (${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ ) is used for the conversion of ethanol (${\mathrm{C}}_2{\mathrm{H}}_2\mathrm{OH}$) to ethanoic acid (${\mathrm{CH}}_3\mathrm{COOH}$).

Ethanol and ethanoic acid can be distinguished by two tests given below:

(i) Litmus test:

Ethanoic acid turns the color of litmus paper from blue to red. Ethanol does not turn the color of litmus paper. Thus, the change in the color of litmus paper can distinguish between ethanol and ethanoic acid.

(ii) Sodium hydrogen carbonate test:

Ethanoic acid gives the sodium hydrogen carbonate test. The reaction of ethanoic acid with sodium hydrogen carbonate (${\mathrm{NaHCO}}_3$) is written as:

${\mathrm{CH}}_3\mathrm{COOH}+{\mathrm{NaHCO}}_3\to {\mathrm{CH}}_3\mathrm{COONa}+{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}$

Carbon dioxide (${\mathrm{CO}}_2$) gas is liberated which turns lime water milky.

Ethanol does not give sodium hydrogen carbonate test.