What is a simple test to distinguish between an aliphatic compound and an aromatic compound?

Answer 1

Huckels rule. 4n + 2 whereby n is any integer for example 1,2,3 etc. Aromatic compounds will obey huckels rule:-

(4 x (1)) + 2 = 6

(4 x (2)) + 2 = 10

(4 x (3)) + 2 = 14

Taking benzene as an example...is it aromatic?

Is a six membered ring with 3 double bonds, so 6pi electrons thus obeys huckels rule and is aromatic. Negative charges also count as 2pi electrons and positive charges on a molecule are ignored entirely.

Answer 2

The aromatic compounds have higher ratio of carbon as compare to corresponding aliphatic compounds so aromatic compounds burn with soot (dark black smoke) due to unburned particles of carbon while aliphatic compounds burn without soot (Exceptions are there) so this is a simple test to distinguish between two types of compounds.

Answer 3

If the compound is in solid form, take a little amount of it in a spatula and put it over flame. If the compounds burns with sooty yellow flame, then it is an aromatic organic compound. But if t burns with non-luminous flame, it is aliphatic.

Answer 4

In general, aromatic compounds give bands above 3000cm-1 (this is the C-H stretching). Aliphatic C-H bonds give bands solely below 3000cm-1.

Answer 5

Aromatic will turn bright colors in CHCl3 and AlCl3