Question

How can you tell the difference between an ester, ketone, carboxylic acid, aldehyde, amines, amides and phenol?

Answer 1

Let that be ester, ketone, carboxylic acid, aldehyde, amines, amides or phenol; each one of them is just the additional part to a molecule hampering its general physical and chemical properties. But each one of them added to the molecule defines new properties different from each other.

Complete answer:
Let us see all of them one by one;
Ester-
A chemical compound in which at least one hydroxyl group is replaced by an alkoxy group.

Ketone-
It is a functional group attached to a molecular chain. It contains a carbonyl group.

Carboxylic acid-
It is an organic acid that contains a carboxyl group. They occur widely and the most common ones are amino acids and fatty acids.

Aldehyde-
It is a functional group with the structure -CHO, consisting of carbonyl in the centre.

Amines-
These are the organic compounds that contain nitrogen atoms with a lone pair of electrons.

Amides-
They are the organic compounds that contain a functional group consisting of an acyl group linked to a nitrogen atom.

Phenol-
It is an aromatic organic compound, basically we can consider it as an alcohol. It consists of a phenyl group bonded to the hydroxyl group.

Now, by looking at the above diagrams we can find the differences easily.

Note:
During old times, scientists used to use Infra-red spectroscopy to determine the differences between the above given compounds. Modern methods include X-ray crystallography and NMR spectroscopy.