Enumerate the reactions of `D`-Glucose which cannot be explained by its open-chain structure.

Explanation

(a) `D(+) -` glucose does not undergo certain characteristic reactions of aldehydes, e.g., glucose does not form `NaHSO_(3)` addition product.
(b) Glucose reacts with `NH_(2)OH` to form an oxime but glucose pentaccetate does not. This implies that the aldehydic group is absent in glucose pentaccetate.
(c) `D - (+) -` glucose exists in two stereoisomeric forms, i.e., `alpha`-glucose and `beta-`glucose.
(d) Both `alpha - D -` glucose and `beta - D -` glucose undergo mutarotation in aqueous solution. Although the crystalline forms of `alpha -` and `beta - D (+) -` glucose are quite stable in aqueous solution but each form slowly changes into an equilibrium. mixture of both.
(e) `D(+)-` glucose forms two isomeric methyl glucosides. Aldehydes normally react with two moles of methanol per mole of the aldehyde to form an acetal but `D(+) -`glucose when treated with methanol in presence of dry HCl gas, reacts with only one mole of methanol per mole of glucose to form a mixture of two methyl `D-`glucosides i.e., methyl `- alpha - D -`glucoside (melting point 43.8 K, specific rotation `+158^(@)`) and methyl `-beta - D -` glucoside (melthing point 308 K, specific rotation `-33^(@)`)