Benedict's reagent, copper (II) citrate, a blue solution, is used to identify reducing sugars in solution. The copper is reduced to Cu(I), forming a red precipitate of Cu2O. Benedict's reagent reacts with the open chain form of glucose, yet it can be used to quantify total concentration of glucose in solution (it is the basis of ‘clinitabs' that are uses to measure glucose in urine). Explain, using chemical structures, how Benedict's reagent works.