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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3ro074

cis-But-2-ene and trans-but-2-ene are separately treated with cold, dilute, alkaline . Which statements are correct?

  1. Acis-But-2-ene gives meso-butane-2,3-diol.
  2. Btrans-But-2-ene gives a racemic mixture of (2R,3R)- and (2S,3S)-butane-2,3-diol.
  3. Ccis-But-2-ene gives a racemic mixture of butane-2,3-diols.
  4. DBoth alkenes give the same stereoisomeric product.

Answer: A, B

The reaction is a syn addition of two OH groups. Syn addition to the cis alkene gives the meso (2R,3S) diol. Syn addition to the trans alkene gives the (2R,3R) and (2S,3S) pair in equal amounts. Statements 1 and 2 are correct.
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