Q.Assertion: 2,2-dimethylpropanoic acid does not give the HVZ reaction. Reason: 2,2-dimethylpropanoic acid does not have an alpha-hydrogen atom. a) if both assertion and reason are true and reason is the correct explanation of assertion. b) if both assertion and reason are true but reason is not the correct explanation of assertion. c) assertion is true but reason is false d) both assertion and reason are false.

Step 1. 2,2-dimethylpropanoic acid is (CH3)3C-COOH -- its alpha-carbon (the carbon directly bonded to -COOH) is the quaternary carbon bearing three methyl groups and the -COOH itself, with NO hydrogen left on it at all.

Step 2. The HVZ reaction (Section 12.12.D.1) specifically requires an alpha-HYDROGEN, since the mechanism halogenates the acid (via its acid-halide enol form) at that exact position. …

Draw out the full structure of 2,2-dimethylpropanoic acid and check its alpha-carbon's substituents directly -- three methyls plus -COOH leaves no room for a hydr …

• Confusing the alpha-carbon (directly bonded to -COOH) with one of the three methyl groups (which DO have hydrogens) -- the HVZ reaction specifically needs a hydrogen …