Question

The general formula of arenes is:
(A) $$C_n{H}_{2n}$$
(B) $$C_n{H}_{2n-4}$$
(C) $$C_n{H}_{2n+2}$$
(D) $$C_n{H}_{2n-6m}$$

Answer 1

Hint: To know about arenes you must be knowing some of the characteristics about arenes. Arenes are also called aromatic compounds. Examples of arenes include benzene, naphthalene, anthracene, etc. You know the formula of these compounds, so now you can guess the general formula.

Complete step by step answer:
Arenes are also known as aromatic compounds. Kekule was the one who first used aromatic compounds. He used this structure in order to represent benzene and its derivatives. Aromatic compounds are said to be a series of compounds which contain one or more benzene rings. Some of the examples of arenes are benzene, phenol, toluene, naphthalene, phenanthrene and anthracene.
Aromatic hydrocarbons are classified into two types, they are:
- Benzenoid compound
Those compounds that contain benzene rings are called Benzenoid compounds.
- Non benzenoid compound:
Those compounds that do not contain the benzene rings are called Non benzenoid rings.
The aromatic compounds or arenes are having the general formula of $$C_n{H}_{2n-6m}$$where n is the number of atoms present and m is the number of rings.
Aromatic compounds are having the following properties such as
- Aromatic compounds will undergo nucleophilic and electrophilic reactions.
- Aromatic compounds are said to be aromatic because they follow Huckel’s rule.
- They are highly stable and less reactive.
- They are immiscible in water.
As arenes are said to have the general formula of $$C_n{H}_{2n-6m}$$.
Therefore, the correct answer is option (D) $$C_n{H}_{2n-6m}$$
Additional information:
Comparison between Aliphatic and aromatic compounds.

ALIPHATIC	AROMATIC
Aliphatic compounds are having linear as well as cyclic structure.	Aromatic compounds are having cyclic structure.
Presence of unpleasant odour	Presence of pleasant odour.
Have both saturated and unsaturated compounds.	Have unsaturated compounds alone.
Carbon-to-hydrogen ratio is high.	Carbon-to-hydrogen ratio is high.
No delocalisation of pi electrons	Delocalisation of pi electrons.

Note: Aromaticity of any compound is determined using a rule which is known as Huckel’s Rule. When the compound follows these rules, it is said to be aromatic. When the molecule is having a cyclic planar structure with $$s{p}^2$$ hybridised orbital and contains (4n+2) π electrons in the molecular orbital, then it is said to be aromatic.