What is the molecular formula of glyceraldehyde?

From the following, the correct statements about polysaccharides are:
$(I)$ Starch is a polymer of $\alpha-D(+)$-glucose.
$(II)$ Amylose component of starch is not soluble in water.
$(III)$ Amylose is a branched chain polymer of $\alpha-D(+)$-glucose.
$(IV)$ Cellulose is a straight chain polymer of $\beta-D(+)$-glucose units.

The correct corresponding order of names of four aldoses with configurations given below,respectively,is:
$(1)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ (both $-OH$ on right)
$(2)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ ($-OH$ on left at $C-2$,right at $C-3$)
$(3)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ (both $-OH$ on left)
$(4)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ ($-OH$ on right at $C-2$,left at $C-3$)

Predict the product of the following reaction:

Which carbohydrate is present in the liver?

The optical rotation of the $\alpha$-form of a pyranose is $+150.7^{\circ}$,that of the $\beta$-form is $+52.8^{\circ}$. In solution,an equilibrium mixture of these anomers has an optical rotation of $+80.2^{\circ}$. The percentage of the $\alpha$-form in the equilibrium mixture is $....... \%$.