Nomenclature Of Organic Compounds

The given compound is a halogen-substituted benzene. The IUPAC name is 3 – Bromo– 1 – chlorocyclohexene.
- The first step is to number the positions of the substituents on the benzene ring. We begin by numbering the ring to give the lowest possible numbers to the substituents.
- Chlorine (Cl) is at position 1, and bromine (Br) is at position 3. The substituents are located at the 1 and 3 positions on the benzene ring.

Step 1: Number the positions of the substituents on the benzene ring starting from the substituent that provides the lowest numbering.


Step 2: Name the compound according to the position of the substituents.

To arrange these compounds in increasing order of acid strength, we consider the ability of these compounds to donate a proton. The stronger the ability to donate a proton (H ), the stronger the acid.
1. Ethanol (CH CH OH): Ethanol has a hydroxyl group (-OH) but it is a very weak acid compared to water or phenol.
2. Water (H O): Water is neutral but can act as a weak acid, donating a proton to form .
3. Phenol (C H OH): Phenol is a stronger acid than both ethanol and water due to the resonance stabilization of the phenoxide ion (C H O ) after proton donation.
Thus, the increasing order of acid strength is:

The compound consists of a methyl group and a chlorine atom attached to a benzene ring. The correct IUPAC name is 1-Chloro-4-Methylbenzene, where the numbering starts from the position of the chlorine atom, followed by the methyl group.
Step 2: Thus, the correct answer is option (3).

The IUPAC name is based on the longest chain containing the amine group and the substituents. Here, the longest chain is 3 carbons (propan), with two substituents on the nitrogen (ethyl and methyl). Thus, the correct name is N-ethyl-N-methylpropan-1-amine.