Glucose (Simple Chemical Reactions):- Glucose occurs in nature in Free States as well as in combined state. In Free State, it occurs in sweet fruits and honey. Ripe grapes are rich in glucose and hence the name grape sugar. In combined state glucose is present in di- and poly-sacccharides. Maltose and starch on hydrolysis yield only glucose.

Prepration:-

(1) By hydrolysis of Cane sugar:- In laboratory glucose can be prepared by hydrolysis of cane sugar in the presence of alcohol using dil HCl. Glucose and Fructose are formed. Glucose being less soluble in ethyl alcohol than fructose crystallizes out.

C₁₂H₂₂O₁₁ + H₂O C₆H₁₂O₆ + C₆H₁₂O₆

Sucrose                            Glucose     Fructose

(2) By the hydrolysis of Starch:- Glucose is commercially prepared by the hydrolysis of starch by boiling it with dil H₂SO₄ at 393 K at a pressure of 2-3 bar.

(C₆H₁₀O₅)_n + n H₂O n C₆H₁₂O₆

Starch                                    Glucose