Isomers of C₃H₇Br: constitutional and stereoisomers Steps:

• Calculate degree of unsaturation: (2C + 2 - H - X)/2 = (8 - 7 - 1)/2 = 0, so acyclic saturated bromoalkane.
• Identify constitutional isomers by placing Br on different carbons: 1-bromopropane (CH₃CH₂CH₂Br) and 2-bromopropane ((CH₃)₂CHBr).
• Assess chirality: 1-bromopropane's Br-carbon has two H atoms, achiral; 2-bromopropane's central C has Br, H, CH₃, CH₃ (identical groups), achiral.
• No stereoisomers possible, so total isomers = 2.

Why A is correct:

• C₃H₇Br has exactly two constitutional isomers, both achiral, per isomer classification rules.

Why the others are wrong:

• B. 3: Mistake from assuming 2-bromopropane chiral (ignores identical methyl groups).
• C. 4: Matches constitutional isomers of C₄H₉Br, not C₃H₇Br.
• D. 5: Matches total isomers of C₄H₉Br including 2-bromobutane enantiomers.

Final answer: A