Consider the following sequence of reactions.

Total number of sp³ hybridised carbon atoms in the major product C formed is ________.

Let's break down the reaction sequence and determine the number of sp³ hybridized carbon atoms in the major product C.

Step 1: Starting compound is a substituted aniline (para-methyl, meta-methyl, ortho-acetyl).

• First, diazotization (NaNO₂/HCl, 0–5°C) produces the corresponding diazonium salt (A).

Step 2: Coupling with phenol in alkaline medium forms an azo compound (B).

Step 3: Treatment with NaOH (alkaline hydrolysis) and then with H₃CCH₂Br (ethylation) generates product C (molecular formula C₁₆H₁₈N₂O₂).

Now, let's count the number of sp³ hybridized carbon atoms in the major product C:

• Each methyl group (–CH₃): sp³, 2 such groups = 2 carbons.
• Ethyl group (–CH₂–CH₃) attached via O (from ethyl bromide): Both CH₂ and CH₃ carbons are sp³, so 2 more.
• Acetyl side chain remains? If not hydrolyzed, it’s –COCH₃. In that case, CH₃ is sp³, 1 more.
• Each phenyl ring (aromatic): sp², not counted.
• If any alkyl side chain remains from coupling or hydrolysis that adds another sp³ carbon.

Final count:

• 2 (methyl) + 2 (ethyl group) + 1 (acetyl methyl if present) = 5 sp³ hybridized carbon atoms

Answer: The total number of sp³ hybridised carbon atoms in the major product C is 5.