Question #7c641

1 Answer
Mar 25, 2017

D-Galactose is a dextrorotatory compound.

Explanation:

D-galactose exists almost completely in two cyclic forms.

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The specific rotation of α-D-galactose is +150.7°, and that of β-D-galactose is +52.8°.

When an aqueous solution of the two forms is allowed to equilibrate, the specific rotation is +80.2°.

Similarly, the specific rotation of α-L-galactose is -150.7°, and that of β-L-galactose
is -52.8°.

The specific rotation of an equilibrium mixture is -80.2°.