When (R)-2-bromobutane is heated in water ,the sn1substitution proceeds twice as fast as sn2 . calculate the appropriae enantiomeriexcess and the specific rotation of the product. The specific rotation of r-butanolis +13.5

Dear Student,

When (R)-2-bromobutane is heated in water, the S_N¹ substitution reaction occurs which produces a racemic mixture of (R)-2-butanol and (S)-2-butanol. Since a racemic mixture contains equal amounts of both the enantiomers, therefore, the sepecific rotation of one enantiomer cancels out the specific rotation of other enantiomer i.e. R-Butanol has specific rotation +13.5, so S-Butanol will have specific rotation -13.5.
The overall specific rotation for the mixture is +13.5+(-13.5)=0
$$\begin{gathered} \mathrm{Enatiomeric} \mathrm{excess}, \mathrm{ee}=\frac{\mathrm{specific} \mathrm{rotation} \mathrm{of} \mathrm{mixture}}{\mathrm{specific} \mathrm{rotation} \mathrm{of} \mathrm{pure} \mathrm{enatiomer}}\times 100 \\ \mathrm{or}, \mathrm{ee}=\frac{0}{-13.5}\times 100=0 \\ \mathrm{i}.\mathrm{e}. \mathrm{the} \mathrm{enantiomers} \mathrm{are} \mathrm{in} \mathrm{equal} \mathrm{quantity}. \end{gathered}$$