Interconversion of D-galactose forms. A freshly prepared solution of the form of D-galactose (1 g/mL in a 1 dm polarimetric tube) shows an optical rotation of + 150.7 O . When left undisturbed for a long period of time, the rotation gradually decreases until it reaches an equilibrium value equal to +80.2 O . In contrast, a freshly prepared solution (1g/mL) of the form shows an optical rotation of only +52.8 O . When this solution is allowed to stand for several hours the rotation increases until the equilibrium value equals +80.2 O , followed value observed for -D-galactose. a) Write the Haworth projection formulas for the and forms of D-galactose. What characteristic distinguishes the two forms? b) Why does the rotation of a freshly prepared solution of the form gradually decrease with time? Explain why solutions of the forms and (equal deconcentration) reach the same value of optical rotation at equilibrium?