(+)-2-iodobutane loses its optical activity when Nal is added to its acetone solution. Explain.

(+)-2-iodobutane loses its optical activity when Nal is added to its a

1.	(+)-2-iodobutane loses its optical activity when Nal is added to its acetone solution. Explain.
Answer» Solution :(+)-2-iodobutance reacts with NAI in acetone to form `(+-)`. 2-iodobutane, which leads to reacemisation. Thus the solution become optically inactive. Each `S_(N)2` attack on (+)-2-iodobutane by `I^(THETA)` occurs with inversion of CONFIGURATION resulting in the formation of (-)-2-iodobutance. As the concentration of the (-)-enantiomer in the reaction MIXTURE increases, its tendency to reacts with `I^(Theta)` forming a(+)-enantimer increases. At a certain time, the mixture contains equimolar amounts of (+) and (-) -2- iodobutane. Since both the enantiomers react with `I^(Theta)` at the same rate (because the ACTIVATION energy is the same), their composition remains unchanged. As the rotation caused by the molecules of one enantiomer is exactly cancelled by equal and opposite rotation caused by the same number of molecules of the other enantiomer, the mixture is optically inactive.