30 Questions
What is the general composition of carbohydrates?
Carbon, oxygen, and hydrogen
Which functional group is present in carbohydrates?
Aldehydic or ketonic functional group
What is the purpose of Molisch's Test?
To detect carbohydrates in a solution
What is the reaction underlying Molisch's Test?
Formation of Furfural and its derivatives
What is the purpose of Fehling's Test?
To detect the presence of reducing sugars and non-reducing sugars
Who developed the Fehling's Test?
H.C. Von Fehling
What is the typical colour of Fehling's A solution?
Blue
What is the role of tartrate tetra-anions in Fehling's solution?
Chelating agent
How are Fehling's A and B solutions mixed to prepare the final Fehling solution?
In equal volumes
What is the purpose of the control tube in the Fehling's test?
To contain distilled water
What is the expected outcome of the Fehling's test?
Formation of a red precipitate
In which condition are the tubes containing the sample and Fehling's solution placed?
In a water bath
What is the primary purpose of the Biuret test?
To demonstrate the presence of the peptide bond
What is the expected outcome of the Iodine test if starch is present?
A blue-black colored complex
What is the purpose of the control sample in the Iodine test?
To compare the results with the test sample
What is the initial step in the Biuret test procedure?
Add 2 cm3 of the liquid food sample to a clean, dry test tube
What is the effect of heating the test tubes in the Iodine test?
The color that develops in the test tubes disappears
What is the quantity of the liquid sample required for the Iodine test?
1 ml
What is the indicator of a positive Benedict's test?
Formation of a reddish brown precipitate
What is the purpose of heating the solution in a boiling water bath during Benedict's test?
To facilitate the reaction between the sample and Benedict's reagent
Which of the following sugars does not give a positive Benedict's test?
Sucrose
What is the function of CuSO4 in Benedict's test?
To act as an indicator for the presence of reducing sugars
What is the purpose of Barfoed's test?
To distinguish between monosaccharides and disaccharides
What happens to sucrose when it undergoes Barfoed's test?
It undergoes hydrolysis in the presence of an acid
What is the primary purpose of Barfoed's test?
To differentiate between monosaccharides and disaccharides
What is the role of the acidic medium in Barfoed's test?
It enhances the reduction of cupric ions to cuprous ions
What is the outcome of the test if red precipitates are formed after the initial 5 minutes?
The presence of a monosaccharide is indicated
Why is it necessary to allow the solution to cool gradually at room temperature?
To prevent the decomposition of the test solution
What happens to disaccharides when the heating period is increased?
They are converted to monosaccharides
What is the name of the test that is often used to detect the presence of protein in a given solution?
Biuret test
This quiz covers the laboratory tests used to detect carbohydrates, including Molisch's Test and others. Learn about the different methods used to identify carbohydrates in a solution. Get familiar with the important tests for carbohydrate detection and their procedures.
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