Question

The IUPAC name of $C{H_3}C{H_2}COCl$ is:
A.Propanoyl chloride
B.Ethanoyl chloride
C.Acetyl chloride
D.Chloroethane

Answer 1

The given compound is an organic compound with the carbonyl group and chlorine as the functional groups. To understand the method to name this compound, we must first understand the nomenclature rules of IUPAC.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
The nomenclature rules of IUPAC can be given as:
1.Find the longest chain of carbon atoms. This will be the parent chain of the compound.
2.Then identify all the substituents of the functional groups.
3.While numbering the functional group, the numbering on the parent chain should be such that it should be closest to the terminal carbon atom.
4.If the same functional group is occurring more than once, then while mentioning the functional group in the name of the hydrocarbon, appropriate position numbering should be mentioned. In addition, the number of times the substituent group occurs is indicated by a prefix (di, tri, tetra, etc.).
5.If chains of equal length are competing for selection as the parent chain, then the choice goes in series to:
a) the chain which has the greatest number of side chains.
b) the chain whose substituents have the lowest- numbers.
c) the chain having the greatest number of carbon atoms in the smaller side chain.
d)the chain having the least branched side chains.
Now, we can observe that there are 3 carbon atoms in the parent chain of the compound. So, the parent chain is propane. Now one of the carbon atoms of this chain has a carboxyl group along with a chlorine substituent. To address the carbonyl group, we end the name of the parent chain with the suffix ‘-oyl’. Hence the parent chain is now Propanoyl. Now the substituent can also be also be addressed using a suffix for the same.
Hence, the name of the given compound $C{H_3}C{H_2}COCl$ is Propanoyl chloride.
Hence, Option A is the correct option

Note: The functional group of chlorine is not named as an individual substituted with a position number because it is a part of the carbonyl group. This terminal carbonyl group represents the acidic group, where the hydroxyl group is substituted by chlorine.