An aqueous solution of glucose behaves like an aldehyde because
Because it is a cyclic hemiacetal and the predominant form is in equilibrium with the free aldehyde form. like glucose has one aldehyde group and five hydroxyl groups and can form an intramolecular cyclic hemiacetal. In aqueous solution, glucose exists in open and closed form. When the process of converting from closed to open form and back to closed form, the rotation of c1 and c2 has taken place, this rotation produces the two anomers α and β. Thus, the equilibrium of α and β in solution is the result of this mutarotation. In glucose, the β anomer is more predominant than the α anomer.
periodic trends are an atom getting bigger as the number of electron shells increases, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom decreases as you move from left to right over a period of time.
if you mean hydrogen and oxygen then water is the product