NEET levelSingle correct optionDifficulty 1 of 3o3113
(CHX3)X3C−Br undergoes substitution with hydroxide in aqueous acetone by the SN1 mechanism. If the concentration of OHX− is tripled while the concentration of the bromide, the solvent and the temperature are unchanged (ignore salt effects), the rate of disappearance of the bromide will
Aremain essentially unchanged
Bbecome nine times larger
Cbecome three times larger
Dbecome one third
Answer: A
SN1 has rate =k[RBr]; the slow step is ionisation of the C-Br bond and the nucleophile enters only after the rate-determining step. Changing [OHX−] therefore does not change the rate of consumption of the substrate.