IUPAC name of Acetanilide is

N-Phenylethanamide

The correct answer is option 2. N-Phenylethanamide.

The IUPAC name of a compound is determined by following a set of rules established by the International Union of Pure and Applied Chemistry (IUPAC). Let's break down the IUPAC name for acetanilide:

The molecular structure of acetanilide is:



Here, CH₃ represents a methyl group, C(O) represents a carbonyl group, and NHPh represents an amino group attached to a phenyl (Ph) group.
Now, let's apply the IUPAC naming rules:
1. Identify the longest carbon chain: In this case, we have a carbonyl group \((>C=O)\) attached to a two-carbon chain.

2. Number the carbon atoms in the chain: Start numbering from the carbon of the carbonyl group. In acetanilide, the carbonyl carbon is part of a two-carbon chain, and it is the first carbon.

3. Substitute groups: Identify and name any substituent groups. In this case, we have a methyl group (CH₃) attached to the first carbon, and an amino group (NHPh) attached to the second carbon.

4. Assign a number to each substituent:  The methyl group is on carbon 1, and the amino group is on carbon 2.
Putting it all together:
The IUPAC name for acetanilide is N-Phenylethanamide.