Question

How would you distinguish experimentally between an alcohol and a carboxylic acid on the basis of a chemical property?

Answer 1

Step 1:

Alcohol is a hydrocarbon that contains $-\mathrm{OH}$ as a functional group. An example of alcohol is ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$

Carboxylic acid is a hydrocarbon that contains $-\mathrm{COOH}$ as functional group. An example of carboxylic acid is ${\mathrm{CH}}_3\mathrm{COOH}$

Step 2: Chemical Test:

There is a test to distinguish between alcohol and carboxylic acid:

Treatment with sodium carbonate

When Sodium carbonate $\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$ is added to carboxylic acid it gives effervescence.

$$\begin{gathered} 2{\mathrm{CH}}_3\mathrm{COOH}+{\mathrm{Na}}_2{\mathrm{CO}}_3\to 2{\mathrm{CH}}_3\mathrm{COONa}+{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O} \\ (\mathrm{Carboxylic}(\mathrm{Sodium}(\mathrm{Sodium}\mathrm{acetate}) \\ \mathrm{acid})\mathrm{carbonate}) \end{gathered}$$

But when Sodium carbonate $\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$ is added to alcohol then there is no reaction.

$$\begin{gathered} {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}+{\mathrm{Na}}_2{\mathrm{CO}}_3\to \mathrm{No}\mathrm{reaction} \\ \left(\mathrm{Alcohol}\right)(\mathrm{sodium} \\ \mathrm{carbonate}) \end{gathered}$$