The specific rotation of freshly prepared solution of `alpha-D-` glucose changes from a value of `X^(@)` to a constant value of `Y^(@)`. The values of `X` and `Y` are respectively

Options

A. `112^(@)` and `52.5^(@)`
B. `52.5^(@)` and `112^(@)`
C. `19^(@)` and `52.5^(@)`
D. `52.5^(@)` and `19^(@)`

Answer

A

Explanation

A solution of ordinary `D - (+) -` glucose, the `alpha`- form, `(mp 146^(@)C)` has an initial specific rotation of `112^(@)C`, but, ultimately, the specific rotation of this solution falls to `+ 52.7^(@)`. A solution of the second form of `D - (+) -` glucose `(mp 150^(@)C)` has an initial specific rotation of `+ 18.7^(@)C`, but slowly, the specific rotation of this solution rises to `+ 52.7^(@)`.