Benedict solution

Benedict solution Aqueous solution of Na2C03, CuSO, and sodium citrate used for testing for reducing agents, particularly sugars, which give red-yellow colours or precipitates. 

A re-examination of the behavior of compounds 25, 26, and 33 towards base, under equal conditions of concentration and temperature, revealed40 the following quantitative differences. Whereas compound 25 reduces (the strongly alkaline) Fehling157 as well as (the weakly basic) Benedict solution,158 compound 33 reduces the latter only. Compound 26, however, as reported,25 shows no reducing... 

BENEDICT SOLUTION. In its original, classical form, this was ail alkaline solution of copper hydroxide and sodium citrate in sodium carbonate used either as a mild oxidizing agent or as a test for easily oxidizable groups such as aldehyde groups. The formation of cuprous oxide is a positive test, its color red, but often yellow al first. Many other forms of this solution have been developed. Glucose reacts with Benedict solution to form cuprous oxide. 

Benedict solution. A water solution of sodium carbonate, copper sulfate, and sodium citrate. The blue color changes to a red, orange, or yellow precipitate or suspension in the presence of a reducing sugar such as glucose, and is therefore used in testing for such materials, especially for urinalysis in the treatment of diabetes. 

Benedict solution Bennett fracture Berger disease Bernard syndrome Besnier-Boeck disease Bing sign... 

Benedict s solution contains cupric ion (Cu ) as a complex ion in a basic solution like Tollens reagent, it converts aldehydes to carboxylic acids. In this reaction, Cu is reduced to Cu, which forms as a brick-red precipitate, CU2O. Benedicts solution has the characteristic blue color of Cu, which fades as the red precipitate of CU2O forms. Benedicts solution is basic, and in a basic solution, a carboxyhc acid is converted to its conjugate base, that is, a carboxylate anion. 

What is observed when an aldehyde reacts with Benedicts solution What is observed when an aldehyde reacts with Tollens reagent ... 

The anomeric glycosides are diastereomers with different physical properties. Like ordinary acetals and ketals, they are stable in neutral or basic solution. Therefore, they are not reducing sugars because they do not hydrolyze to form a free aldehyde group in Benedicts solution, which is basic. However, glycosides are hydrolyzed in acid solution by the reverse of the reactions shown in Figure 26.7. 

Benedict s solution Is prepared as follows. Dissolve 86-5 g. of crystallised sodium citrate (2Na,C,H(0, l 1H,0) and 50 g. of anhydrous sodium carbonate in about 350 ml. of water. Filter, if necessary. Add a solution of 8-65 g. of crystallised copper Sulphate in 50 ml. of water with constant stirring. Dilute to 500 ml. The resulting solution should be perfectly clear if it is not, pour it through a fluted filter paper. 

Aromatic aldehydes react with the dimedone reagent (Section 111,70,2). All aromatic aldehydes (i) reduce ammoniacal silver nitrate solution and (ii) restore the colour of SchifiF s reagent many react with sodium bisulphite solution. They do not, in general, reduce Fehling s solution or Benedict s solution. Unlike aliphatic aldehydes, they usually undergo the Cannizzaro reaction (see Section IV,123) under the influence of sodium hydroxide solution. For full experimental details of the above tests, see under Ali-phalic Aldehydes, Section 111,70. They are easily oxidised by dilute alkaline permanganate solution at the ordinary temperature after removal of the manganese dioxide by sulphur dioxide or by sodium bisulphite, the acid can be obtained by acidification of the solution. 

Benedicts reagent (Section 25 19) A solution containing the citrate complex of CUSO4 It is used to test for the presence of reducing sugars... 

Benedict s qualitative reagent (for glucose) dissolve 173 g of sodium citrate and 100 g of anhydrous sodium carbonate in about 600 mL of water, and dilute to 850 mL dissolve 17.3 g of CUSO4 5H2O in 100 mL of water and dilute to 150 mL this solution is added to the citrate-carbonate solution with constant stirring. See also the quantitative reagent below. 

Benedict s quantitative reagent (sugar in urine) This solution contains 18 g copper sulfate, 100 g of anhydrous sodium carbonate, 200 g of potassium citrate, 125 g of potassium thiocyanate, and 0.25 g of potassium ferrocyanide per liter 1 mL of this solution = 0.002 g sugar. 

A characteristic property of an aldehyde function is its sensitivity to oxidation. A solution of copper(II) sulfate as its citrate complex (Benedict s reagent) is capable of oxidizing aliphatic aldehydes to the conesponding carboxylic acid. 

Fig. 2 Increase in fluorescence of the genuine fluorescence (A) by treatment with Benedict s reagent (B) and immersion in a paraffin solution (C) and reduction of emission intensities with time for the two cumarins umbelliferone and scopoletin (curves).

Note The dipping solution can also be used as a spray solution [7]. Chromatogram of natural product extracts should always be examined under UV light before usin Benedict s reagent, since some natural fluorescences su e reduced to a greater or lesse degree by the reagent. 

Read over the entire laboratory activity. Form a hypothesis about what will happen when you mix the four sugars with the Benedict s solution. Record your hypothesis in the next column. 

Place 5 mL of the solutions of glucose, fructose, sucrose, and starch into the appropriately labeled test tube, numbered 1 through 4. Add 4 mL of Benedict s solution to each test tube and shake each solution until thoroughly mixed. Place each test tube in the boiling-water bath and heat for... 

After 5 minutes of heating, remove the test tubes and place them in the test-tube rack to cool. Record your observations in Data Table 1. Note any color changes or precipitate that formed. Benedict s solution contains an oxidizing agent... 

Data Table 3 Benedict s Test of Hydrolyzed Solutions ... 

Thinking Critically Were reducing sugars detected in the hydrolyzed starch solution using the Benedict s test Was this expected ... 

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