Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Reaction of 2,2-dimethylpropan-1-ol with HBr gives 2-bromo-2-methylbutane as the major product. Reason (R): The reaction involves a 1,2-methyl shift to form a more stable tertiary carbocation. In the light of the above statements, choose the most appropriate answer from the options given below:

Step-by-step solution

2,2-dimethylpropan-1-ol (neopentyl alcohol) is a highly sterically hindered primary alcohol. Upon reaction with HBr , the - OH group is protonated to form a good leaving group ( - OH ₂^+ ). Due to the high instability of a primary carbocation, the departure of the water molecule is accompanied by a simultaneous 1,2-methyl shift from the adjacent quaternary carbon. This rearrangement directly yields a more stable tertiary carbocation (tert-pentyl carbocation). The nucleophilic bromide ion ( Br ^- ) then attacks this