∵ the rate of formation of l-butane-2-ol is twice the rate of formation of d-butane-2-ol.
∴ On hydrolysis of d-2-bromobutane field 66.6% l-butane-2-ol and 33.3% d-butane-2-ol.
∴ enantiomeric excess = 66.6% - 33.3%
ee% = 33.3%
∵ We have given, Specific rotation of pure d-butane-2-ol is +13.5° is specific rotation of pure l-butane-2-ol is -13.5°
as we know
ee% = \(\frac{|\text{Oberserved} \,\alpha|}{|\alpha \,\text{of pure enantiomer of excessisomer}|}\times100\)%
⇒ observed specific rotation = \(\frac{33.3 \times(-13.5)^\circ}{100}\)
= -4.495° or -4.5°
Hence, specific rotation of the product mixture will be -4.5°.
