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JEE Main levelSingle correct optionDifficulty 2 of 3si025

The correct order of speed of turbidity formation (fastest to slowest) with Lucas reagent at room temperature is

  1. A2-methylpropan-2-ol > butan-1-ol > butan-2-ol
  2. Bbutan-1-ol > butan-2-ol > 2-methylpropan-2-ol
  3. Cbutan-2-ol > 2-methylpropan-2-ol > butan-1-ol
  4. D2-methylpropan-2-ol > butan-2-ol > butan-1-ol

Answer: D

The rate follows carbocation stability in the SN1 pathway: tertiary > secondary > primary. Hence 2-methylpropan-2-ol (immediate) > butan-2-ol (about 5 min) > butan-1-ol (no turbidity at room temperature).
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