English Deutsch Français Italiano Español Português 繁體中文 Bahasa Indonesia Tiếng Việt ภาษาไทย
All categories

5 answers

If glucose is present the solution will change colour. The color of the final solution ranges from green to brick red depending on the amount of glucose in the solution (red is more...;)

2006-11-22 07:14:46 · answer #1 · answered by huggz 7 · 1 0

Benedict's reagent (also called Benedict's solution or Benedict's test) is a reagent used as a test for the presence of monosaccharides (such as glucose and fructose); it is also used for some disaccharides like maltose, or more generally for the presence of aldehydes, in a solution.

Benedict's reagent contains blue copper sulphate (CuSO4)· 5H2O which is reduced to red copper oxide by aldehydes, thus oxidizing the aldehydes to carboxylic acids. The copper oxide is insoluble in water and so precipitates. The color of the final solution ranges from green to brick red depending on how many of the copper(II) ions are present. Benedict's test cannot be used to detect the presence of aromatic aldehydes.

When Benedict's is used as a chemical test for the presence of reducing sugars in food, the food sample is dissolved in water and about 5ml of the sample solution is added to 5ml of Benedict's qualitative reagent. The mixture is placed in a boiling waterbath for 5 minutes and any precipitate formed is recorded as a positive for the presence of sugar in the food.

The reason sucrose has a negative result in Benedict's solution is because sucrose is a non-reducing sugar when in contact with a base.

Benedict's reagent can be used to test for the presence of glucose in urine. Glucose found to be present in urine is an indication of diabetes.

5.0ml of Benedict's qualitative solution is mixed with 0.5ml of urine and the mixture is put in a boiling water bath for 5 minutes. The results are recorded thus:

no precipitate —
Green a trace
yellow +
orange ++
red +++

Once sugar is detected in urine, further tests have to be undergone in order to ascertain which sugar is present. Only glucose is indicative of diabetes.

2006-11-22 07:20:20 · answer #2 · answered by DAVID C 6 · 0 0

As far as I recall, it's Brick Red.

(Please bear in mind that it is nearly 20 years since I studied O level Biology!)

2006-11-22 07:14:58 · answer #3 · answered by Anonymous · 0 0

solid orange colour

2006-11-26 04:03:57 · answer #4 · answered by mad Cobra 1 · 0 0

I thought it turned orange.

2006-11-22 07:18:27 · answer #5 · answered by big bang 2 · 0 0

fedest.com, questions and answers