Optically active 2-iodobutane on treatment with sodium iodide in acetone gives a product which does not show optical activity. Explain.

Explanation

Optically active 2-iodobutane dissociated to form iodide ion and the carbocation.
The iodide ion then attacks the flat carbocation from either side resulting in a mixture of two enantiomeric products in equal amounts, which constitutes a racemic mixture which does not show optical activity.