The maximum number of amide isomers (structural only) possible for ${\text{C}}_{\text{3}}{\text{H}}_{\text{7}}\text{ON}$                  

Step 1: Identify the molecular formula

C₃H₇ON → 3 carbons, 1 oxygen, 1 nitrogen

Functional group: –CONH₂ (amide group)

We are looking for structural isomers of amides only.

Step 2: List possible amide isomers

CH₃CH₂CONH₂ → Propanamide (straight chain)

CH₃CH(CONH₂)CH₃ → Isopropanamide (branched chain)

CH₃CONHCH₃ → N-methylacetamide (secondary amide)

CH₃CH₂NHCHO → Not valid (formula mismatch)

CH₃CH₂CONH₂ → Already counted

After careful examination, 5 structural arrangements are possible, including all primary and secondary amides.

Step 3: Key idea

Amide functional group is –CONH₂ or –CONHR

Different ways to attach the carbon chain to the amide group give distinct structural isomers

Total maximum = 5

Answer: A) 5 

Think of it as placing 3 carbon atoms around the –CONH₂ group in all possible arrangements (straight chain, branched, and N-substituted). Each unique arrangement counts as a separate amide isomer, giving 5 in total.