(adapted from Blackburn et al., Laboratory Manual to Accompany World of Chemistry, 2nd ed., (1996)
Saunders College Publishing: Fort Worth) Purpose: To become familiar with some of the characteristic reaction of carbohydrates. To identify an unknown carbohydrate. Caution: Wear eye protection because of the possible shattering of dropped glassware and because acids are used in this experiment. Seliwanoff reagent is resorcinol dissolved in 4M hydrochloric acid.
The acid is corrosive (burns human tissue). If any of this solution gets on your skin, wash the solution off immediately with water. Avoid breathing the vapors of the solution. Protect your hair, clothing and flammable materials from the open flame of the burner. Make sure the beaker is well supported when boiling water so the hot water will not spill on you. Introduction: The carbohydrates (“hydrates of carbon”) are one of the important classed of organic compounds that are composed of the three elements of carbon, hydrogen, and oxygen. These three elements are bonded in such a way that a number of alcohol groups (‐OH) occur along with aldehyde
(‐CHO) or ketone (C=O) group. A simple sugar such as glucose is an example of a carbohydrate with some of these structures. Glucose exists almost entirely in the cyclic form.
Two forms of ‐glucose
The most important simple carbohydrate is glucose. It is found as a major component of other carbohydrates. For example, maltose is a carbohydrate composed of two glucose units. Lactose (milk sugar) contains one glucose unit and one galactose unit, sucrose (table sugar) contains one glucose
unit and one fructose unit, and maltose (malt sugar) contains two glucose units. Each of these disaccharides is composed of two monosaccharides connected to each other with a glycosidic