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What Colour Does Benedict's Solution Change To When Glucose Is Present?

Why Is Benedict's Reagent Used To Test The Presence Of Glucose In Urine? - Quora

Why Is Benedict's Reagent Used To Test The Presence Of Glucose In Urine? - Quora

Why is Benedict's reagent used to test the presence of glucose in urine? Answered Dec 14, 2017 Author has 1.6k answers and 523.5k answer views Benedicts test is used to detect the presence of glucose in urine in patients of diabetes mellitus and renal glycosuria. Presence of other reducing monosaccharides and disaccharide in urine can also be detected using Benedicts reagent, e.g. Benedicts test is positive for the presence of fructose, galactose, lactose and L-xylulose in urine samples of patients with fructosuria, galactosemia, lactosuria and pentosuria, respectively. Due to presence of a free carbonyl group (either CHO or CO group), all monosaccharides (both aldoses and ketoses) and reducing disaccharide like lactose are reducing in nature and reduce the Benedicts reagents to cuprous oxide (Cu2O), a greenish-yellow to brick-red precipitate. In this reaction, the cupric ions (Cu++) of Benedicts reagents are reduced to cuprous ions (Cu+). On the basis of color of cuprous oxide precipitate (greenish-yellow to brick-red precipitate), approximate amount of glucose present in urine can also be determined (see Table). Answered Sep 17, 2016 Author has 56 answers and 33.8k answer views Benedicts Test is used to test for simple carbohydrates. The Benedicts test identifies reducing sugars (monosaccharides and some disaccharides ), which have free ketone or aldehyde functional groups. Some sugars such as glucose are called reducing sugars because they are capable of transferring hydrogen (electrons) to other compounds, a process called reduction. When reducing sugars are mixed with Benedicts reagent and heated, a reduction reaction causes the Benedicts reagent to change color. The color varies from green to dark red (brick) or rusty-brown, depending on the amount of and type of Continue reading >>

Detection Of Carbohydrates, Proteins And Fats (procedure) : Class 11 : Biology : Amrita Online Lab

Detection Of Carbohydrates, Proteins And Fats (procedure) : Class 11 : Biology : Amrita Online Lab

Detection of Carbohydrates, Proteins and Fats Using a dropper, take a small quantity of Benedicts reagent. Add the reagent to the test tube containing banana extract. Boil the sample over a burner for 2 minutes holding the test tube firmly with a test tube holder. Keep shaking the test tube as it is being heated. A brick red precipitate appears, indicating the presence of glucose in the banana extract. On boiling banana extract with the Benedicts reagent, the cupric ion present in the Benedicts reagent is reduced by the reducing agent, sugar, to form a brick red coloured precipitate of cuprous oxide. Using a dropper, take a small quantity of Fehlings solution A. Add the Fehlings solution A to the test tube containing banana extract. Using a dropper, take a small quantity of Fehlings solution B. Add Fehlings solution B to the test tube containing banana extract. Boil the sample over a burner for 2 minutes, holding the test tube firmly with a test tube holder. Keep shaking the test tube while heating. A brick red precipitate appears, indicating the presence of glucose in the banana extract. The cupric ion present in the Fehlings solution is reduced on boiling by the reducing substance, sugar, to form the brick red coloured precipitate of cuprous oxide. Using a dropper, take a small quantity of concentrated HCl. Add 2 to 3 drops of concentrated HCl to the test tube containing sugarcane extract. Boil the sample over a burner for 2 minutes, holding the test tube firmly with a test tube holder. This hydrolyses sucrose into glucose and fructose. Using a dropper, take a small quantity of NaOH solution. Add few drops of NaOH solution to the test tube to make the solution alkaline. Now we can perform Benedicts test to this solution to test for the presence of glucose. Using a dr Continue reading >>

How To Test For Simple Sugars

How To Test For Simple Sugars

Simple sugars, also referred to as monosaccharides, are the basic unit of carbohydrates. Unlike sucrose, which is made of both a glucose and fructose sugar molecule, a simple sugar is either glucose or fructose respectively. Complex sugars, or polysaccharides, are present in foods like vegetables and whole grains. You can test for these simple sugars in your foods by using Benedict’s reagent, a solution made of copper sulfate and sodium hydroxide. You can purchase this solution in a drug store as it used to indicate the presence of sugar in the urine of diabetics. Video of the Day Turn on your hot plate to medium heat and place your beaker filled with 100 mL of water on it. Bring it to a boil. Pour 4 mL of your food sample in a test tube if it is liquid based. If you are testing a solid food, you can use a food processor to puree it by adding a small amount of water or crush the item into a powder using a mortar and pestle. Add water to the powder and pour it in the test tube. Add approximately 1 mL of Benedict’s solution to the test tube using a dropper. Slowly swirl the test tube counterclockwise to distribute the reagent evenly. Place your test tube into the beaker until you note a color change -- this process usually takes five minutes. Examine the color change, if it is present. Benedict’s reagent has a color change gradient from blue, meaning no simple sugars are present, to green, yellow, orange, red and brown. The color sequence indicates the increasing concentration of the simple sugar, with green being the lowest and brown being the highest. Benedict’s reagent Beaker Test tubes and holder Graduated cyclinder Food samples Food processor Water Hot plate Mortar and pestle Dropper Continue reading >>

Benedict's Reagent

Benedict's Reagent

"Benedict's" redirects here. For other uses, see Benedict (disambiguation). Benedict's reagent (often called Benedict's qualitative solution or Benedict's solution) is a chemical reagent named after American chemist Stanley Rossiter Benedict.[1] It is a complex mixture of sodium carbonate, sodium citrate and copper(II) sulfate pentahydrate.[2] It is often used in place of Fehling's solution to detect the presence of reducing sugars. The presence of other reducing substances also gives a positive reaction.[3] Such tests that use this reagent are called the Benedict's tests. A positive test with Benedict's reagent is shown by a color change from clear blue to a brick-red precipitate. Generally, Benedict's test detects the presence of aldehydes and alpha-hydroxy-ketones, also by hemiacetal, including those that occur in certain ketoses. Thus, although the ketose fructose is not strictly a reducing sugar, it is an alpha-hydroxy-ketone, and gives a positive test because it is converted to the aldoses glucose and mannose by the base in the reagent. The principle of Benedict's test is that when reducing sugars are heated in the presence of an alkali they are converted to powerful reducing species known as enediols. Enediols reduce the cupric compounds (Cu2+) present in the Benedict's reagent to cuprous compounds (Cu+) which are precipitated as insoluble red copper(I) oxide(Cu2O). The color of the obtained precipitate gives an idea about the quantity of sugar present in the solution, hence the test is semi-quantitative. A greenish precipitate indicates about 0.5 g% concentration; yellow precipitate indicates 1 g% concentration; orange indicates 1.5 g% and red indicates 2 g% or higher concentration. Benedict's test[edit] To test for the presence of monosaccharides and reducing d Continue reading >>

Benedict's Test : Principle, Reagent Preparation, Procedure And Interpretation | Laboratoryinfo.com

Benedict's Test : Principle, Reagent Preparation, Procedure And Interpretation | Laboratoryinfo.com

By Editorial Team on June 9, 2016 in Biochemistry Benedicts test is used as a simple test for reducing sugars. A reducing sugar is a carbohydrate possessing either a free aldehyde or free ketone functional group as part of its molecular structure. This includes all monosaccharides (eg. glucose, fructose, galactose) and many disaccharides, including lactose and maltose. Benedicts test is most commonly used to test for the presence of glucose in urine. Glucose found to be present in urine is an indication of Diabetes mellitus. Reducing sugars under alkaline condition tautomerise and form enediols. Enediols are powerful reducing agents. They can reduce cupric ions (Cu2+) to cuprous form (Cu+), which is responsible for the change in color of the reaction mixture. This is the basis of Benedicts test. When the conditions are carefully controlled, the colouration developed and the amount of precipitate formed (Cuprous oxide) depends upon the amount of reducing sugars present. Composition and Preparation of Benedicts reagent One litre of Benedicts Solution can be prepared from 100 g of anhydrous sodium carbonate, 173 g of sodium citrate and 17.3 g of copper(II) sulfate pentahydrate. Continue reading >>

What Is Benedict's Test For Reducing Sugars?

What Is Benedict's Test For Reducing Sugars?

Benedict's Test for non-reducing Sugars is a test which determines the presence of non-reducing sugars in a test solution. The principal reagent in Benedict's Test for Reducing Sugars is Benedict's Solution which contains copper(II) sulphate sodium carbonate sodium citrate Sugars are classified as reducing or non-reducing based on their ability to act as a reducing agent during the Benedict's Test. A reducing agent donates electrons during a redox reaction and is itself oxidized. The aldehyde functional group is the reducing agent in reducing sugars. Reducing sugars have either an aldehyde functional group or have a ketone group - in an open chain form - which can be converted into an aldehyde. Reducing sugars are simple sugars and include all monosaccharides and most disaccarides. Some examples of monosaccharides are glucose, fructose and galactose.Examples of reducing disaccharides are lactose and maltose. Note that the disaccharide sucrose is not a reducing sugar. In fact, sucrose is the most common non-reducing sugar. The test may be qualitative, or it may be quantitative. The qualitative test produces a colour change from blue to green to yellow to orange to brick red. The qualitative test is also regarded as semi-quantitative as the colour obtained correlates to the concentration of reducing sugars in the solution ( see observations below). This allows for a rough estimation of the amount of reducing sugar present. The qualitative test is discussed here. The quantitative test involves the use of potassium thicyanate and the production of copper thiocyanate as white or pale green precipitate. This precipitate can then be titrated. A liquid food sample does not need prior preparation except dilution if viscous or concentrated. For a solid sample prepare a test solut Continue reading >>

Reducing Sugars Master Organic Chemistry

Reducing Sugars Master Organic Chemistry

Whats a reducing sugar, and why is it important? Heres a quick summary. Full details in the post below. Q. Can you think of a situation where it might be useful to be able to measure the concentration of glucose in a solution (especially in blood or urine) ? A. Diabetes.Once you have a way of quickly and easily measuring the concentration of sugar, then you can determine how much insulin is needed to counteract it. Next question. What would be an easy, visual way to detect the presence of glucose? Especially something that doesnt require you to be an expert chemist? Ideally, youd like a chemical reaction that results in a color change. Think about pregnancy tests: you just pee on a stick and know within a few minutes whether youre pregnant. You dont need to know any chemistry. Its brainless. 99.999% of people who use this do not know the chemistry behind how it works. And thats OK! A test for blood sugar suitable for diabetics should have a similar ease of use. This brings us (via aldehydes) to the topic ofreducing sugars, since they are the basis of a historically important color-based test for blood glucose. Three Visual Tests For The Presence of Aldehydes Before we get to sugars, lets talk about the oxidation of aldehydes. Weve seen previously that aldehydes are a functional group that can be oxidized relatively easily to carboxylic acids. For example, oxidation of alcohols with a strong oxidant like chromic acid (H2CrO4) results in an aldehyde that is quickly oxidized further to a carboxylic acid. During this process, the aldehyde is oxidized and the oxidizing agent is reduced. Another way of framing this is to say thatthe aldehyde is the reducing agent in this process. The list of reagents that can be used to oxidize aldehydes to carboxylic acids is loooong.Of the Continue reading >>

Simple Chemical Tests For Food

Simple Chemical Tests For Food

Simple chemical tests can identify a number of important compounds in food. Some tests measure the presence of a substance in food, while others can determine the amount of a compound. Examples of important tests are those for the major types of organic compounds: carbohydrates, proteins, and fats. Here are step-by-step instructions to see if foods contain these key nutrients. Carbohydrates in food can take the form of sugars, starches, and fiber. An easy test for sugars uses Benedict's solution to test for simple sugars, such as fructose or glucose. Benedict's solution doesn't identify the specific sugar in a sample, but the color produced by the test can indicate whether a small or large quantity of sugar is present. Benedict's solution is a translucent blue liquid that contains copper sulfate, sodium citrate, and sodium carbonate. How to Test for Sugar Prepare a test sample by mixing a small amount of food with distilled water. In a test tube, add 40 drops of the sample liquid and 10 drops of Benedict's solution. Warm the test tube by placing it in a hot water bath or container of hot tap water for 5 minutes. If sugar is present, the blue color will change to green, yellow, or red, depending on how much sugar is present. Green indicates a lower concentration than yellow, which is lower concentration than red. The different colors may be used to compare the relative amounts of sugar in different foods. You can also test for the amount of sugar rather than its presence or absence using density. This is a popular test for measuring how much sugar is in soft drinks. Protein is an important organic molecule used to build structures, aid in the immune response, and catalyze biochemical reactions. Biuret reagent may be used to test for protein in foods. Biuret reagent is a Continue reading >>

Biology Notes For Igcse 2014

Biology Notes For Igcse 2014

#31 Food test 2 - Benedict's test for Reducing Sugars All simple sugars (e.g.glucose) are reducing sugars. They will react with a blue liquid called Benedict's solution to give a brick red color. We can use this reaction to find out if a food or other substance contains a reducing sugar. heat the mixture for 2-3 minutes in boiling water bath aBRICK RED/ORANGE COLORis a positive result:glucoseis present The closer the color is to brick red, the more reducing sugar is present. Trace amounts of reducing sugars present Moderate amounts of reducing sugars present Large amounts of reducing sugars present Reducing Sugars are sugars that contain aldehydegroups, that are oxidised to carboxylicacids (R-COOH). They are classified as reducing sugars sincethey reduce the blue Cu2+(copper II ions) to Cu+ (copper I ions). These are precipitatedin form of redCu2O (copper oxide), insoluble in water. Illustrations (Photo credit: cccmkc.edu.hk ) When the concentration of reducing sugar is low,the color of theBenedict's test may be light green or pale orange. Videos: Benedict's test for reducing sugars Continue reading >>

Benedicts Reagent Test For Monosaccharides

Benedicts Reagent Test For Monosaccharides

Benedicts reagent test for Monosaccharides In the college days, all of us might have done simple chemistry tests. Generally, chemical tests use reagents to indicate the presence of a specific chemical in an unknown solution. The reagents which are used in the chemical test can cause a unique reaction to occur based on the chemical it reacts with, allowing one to know what chemically is the solution. All these tests are done with excitement and fun, without knowing exact principle and procedure. One of those chemistry tests is Benedicts reagent test. Benedicts reagent test or Benedicts test is used to testing for simple carbohydrates / reducing sugars/ monosaccharides/ disaccharides. A reducing sugar is any sugar that is capable of acting as a reducing agent because it has a free aldehyde group or a free ketone group. Reducing sugars react with amino acids in the Maillard reaction, a series of reactions that occurs while cooking food at high temperatures and that is important in determining the flavour of food. Not all disaccharides will get positive results with this test. There are certain limitations for the disaccharides to give positive results. Benedicts reagent test can be used to test for the presence of glucose in urine, but this test is not recommended or used for the diagnosis of diabetes mellitus. The principle of Benedicts test is that when reducing sugars are heated in the presence of an alkali they get converted to powerful reducing species known as enediols. When Benedicts reagent solution and reducing sugars are heated together, the solution changes its colour to orange-red/ brick red. This colour is due to the presence of simple carbohydrates. In specific, the copper (II) ions in Benedicts solution are reduced to Copper (I) ions, which causes the colou Continue reading >>

Lab Review

Lab Review

These are complex, carbon-containing molecules associated with living organisms. Most also contain hydrogen and oxygen. There are five major types: carbohydrates, lipids, proteins, nucleic acids, and vitamins. We covered the first three types in lab. A review of our carbohydrate test data is provided on this page. Click the molecule types above to link to the associated review material. Benedict's Reagent: A Test for Reducing Sugars Carbohydrates are divided into two groups based on the complexity of their structure. Simple carbohydrates can form either a single ring structure (monosaccharides) or a double ring structure (disaccharides -- formed when a pair of monosaccharides bond). Simple carbohydrates include familiar sugars such the monosaccharides glucose (the basic fuel of cells) and fructose (found in fruits). Common disaccharides include sucrose (table sugar) and lactose (the sugar in milk). Complex carbohydrates (polysaccharides) are chains of many bonded simple carbohydrates, and are often used for energy storage. These include starch, cellulose, and glycogen. One test for the presence of many simple carbohydrates is to use Benedict's reagent. It turns from turquoise to yellow or orange when it reacts with reducing sugars. These are simple carbohydrates with unbound aldehyde or ketone groups. In lab, we used Benedict's reagent to test for one particular reducing sugar: glucose. Benedict's reagent starts out aqua-blue. As it is heated in the presence of reducing sugars, it turns yellow to orange. The "hotter" the final color of the reagent, the higher the concentration of reducing sugar. In general, blue to blue-green or yellow-green is negative, yellowish to bright yellow is a moderate positive, and bright orange is a very strong positive. (See below). 2: Bene Continue reading >>

Biology Lab: Benedict's Reagant

Biology Lab: Benedict's Reagant

The substance to be tested is heated with Benedict's solution; formation of a brick-red precipitate indicates presence of the aldehyde group. Since simple sugars (e.g., glucose) give a positive test, the solution is used to test for the presence of glucose in urine, a symptom of diabetes. Benedict's solution is used to test for simple sugars, such as glucose. It is a clear blue solution of sodium and copper salts. In the presence of simple sugars, the blue solution changes color to green, yellow, and brick-red, depending on the amount of sugar. What does it mean if Benedict 's solution turns orange? In lab, we used Benedict's reagent to test for one particular reducing sugar: glucose. Benedict's reagent starts out aqua-blue. As it is heated in the presence of reducing sugars, it turns yellow to orange Benedict's solution is used to test for simple sugars, such as glucose. It is a clear blue solution of sodium and copper salts. In the presence of simple sugars, the blue solution changes color to green, yellow, and brick-red, depending on the amount of sugar. Starch Test: Add Iodine-KI reagent to a solution or directly on a potato or other materials such as bread, crackers, or flour. A blue-black color results if starch is present. If starch amylose is not present, then the color will stay orange or yellow. Continue reading >>

During A Lab We Mixed Benedict's Reagent With Glucose And After Boiling It, It Turned Lime Green. Why?

During A Lab We Mixed Benedict's Reagent With Glucose And After Boiling It, It Turned Lime Green. Why?

During a lab we mixed Benedict's reagent with glucose and after boiling it, it turned lime green. Why? Benedict's reagent is solution of copper sulfate, sodium carbonate, and sodium citrate. It is used as an indicator to test for the presence of sugars. It works the same way that phenolthalein works with acids and bases. When it is mixed into a solution it will be pink or red without an acid present. As an acid is introduced, it will turn clear. Benedict's reagent works the same way. At the start of a test,... Benedict's reagent is solution of copper sulfate, sodium carbonate, and sodium citrate. It is used as an indicator to test for the presence of sugars. It works the same way that phenolthalein works with acids and bases. When it is mixed into a solution it will be pink or red without an acid present. As an acid is introduced, it will turn clear. Benedict's reagent works the same way. At the start of a test, it is a bluish color. Food is mashed up or ground up and placed in the solution. If no sugars are present, the Benedict's reagent remains the same color. If a color change occurs that means some form of sugar (glucose) is present. The amount of color change indicates the amount of sugars present. It will turn from blue, to green, to yellow, to orange, to pinkish red. Since you know that you put glucose in your heated solution, a color change is expected. Since the color change was to green, not much sugar was added. The only downside to Benedict's solution is that it won't change color in the presence of sucrose. In that case, you would need to boil the sucrose with a bit of dilute hydrochloric acid to split the sucrose into glucose and fructose (which Benedict's reagent does indicate). Continue reading >>

Benedict's Test- Principle, Composition, Preparation, Procedure And Result Interpretation

Benedict's Test- Principle, Composition, Preparation, Procedure And Result Interpretation

Benedicts Test- Principle, Composition, Preparation, Procedure and Result Interpretation 4.3/5 (602) Benedicts Test- Principle, Composition, Preparation, Procedure and Result Interpretation Benedicts Test is used to test for simple carbohydrates.The Benedicts test identifies reducing sugars (monosaccharides and some disaccharides), which have free ketone or aldehyde functional groups.Benedicts solution can be used to test for the presence ofglucose in urine. Some sugars such as glucose are called reducing sugars because they are capable of transferring hydrogens (electrons) to other compounds, a process called reduction. When reducing sugars are mixed with Benedicts reagent and heated, a reduction reaction causes the Benedicts reagent to change color. The color varies from green to dark red (brick) or rusty-brown, depending on the amount of and type of sugar. Benedicts quantitative reagent contains potassium thiocyanate and is used to determine how much reducing sugar is present. This solution forms a copper thiocyanate precipitate which is white and can be used in a titration. The titration should be repeated with 1% glucose solution instead of the sample for calibration When Benedicts solution and simple carbohydrates are heated, the solution changes to orange red/ brick red. This reaction is caused by the reducing property of simple carbohydrates. The copper (II) ions in the Benedicts solution are reduced to Copper (I) ions, which causes the color change. The red copper(I) oxide formed is insoluble in water and is precipitated out of solution. This accounts for the precipitate formed.As the concentration of reducing sugar increases, the nearer the final colour is to brick-red and the greater the precipitate formed.Sometimes a brick red solid, copper oxide, precipita Continue reading >>

 Benedict's Solution - (2018 - Updated)

Benedict's Solution - (2018 - Updated)

Image 3: Test tubes containing benedicts solution testing for sugars Benedicts solution is used in testing simple carbohydrates. The test helps in identifying reducing sugar such as monosaccharides (glucose, fructose, and galactose) and a few disaccharides (lactose and maltose). They have free ketone. With the help of benedicts solution, health care professionals will be able to detect the presence of glucose in urine. What is the implication of reducing sugars? This type of sugar has the ability to transfer hydrogens to other compounds through the process called reduction. The color of the benedicts solution changes if the reducing sugar is mixed with the Benedicts reagent and put under a fire. Through Benedicts test, the sugar in the urine will be detected, which helps in diagnosing diabetes mellitus. (2, 3) Benedicts reagent formula is made up of potassium thiocyanate, which helps determine the amount of reducing sugar. It will then form a copper thiocyanate precipitate, which is white in color and useful in titration. For calibration, the titration is repeated using a 1% glucose solution. As with the benedicts solution color change, there is an explanation to that. If the benedicts solution and simple carbohydrates are heated, the benedicts solution will change its color to orange red or brick red. It is an indication that the property of simple carbohydrate is reduced. The copper ion in the benedicts solution is reduced, which causes the color to change. It forms a red copper (I) oxide, which is water insoluble. It will then precipitate out of solution leading to the formation of precipitate. It increases the concentration of reducing sugar. The final color is brick red, which indicates that a greater precipitate is formed. (5, 7) Some complex carbohydrates like s Continue reading >>

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