12 Questions
What is the purpose of Molisch Test?
To detect carbohydrates
Which reagent is used in Benedict's Test?
Benedict's reagent
What color indicates a positive Benedict's Test?
Brick-red
Which test is specifically used to detect pentoses?
Bial's Test
What is the purpose of Barfoed's Test?
To detect monosaccharides
In Bial's Test, what is the basis for detecting pentoses?
Dehydration into furfural and condensation with orcinol
What is the purpose of SELIWANOFF’S TEST?
To differentiate between ketoses and aldoses
Which of the following reagents is used in Fehling’s test?
Fehling’s A and Fehling’s B
What does a positive result in the IODINE TEST indicate?
Presence of starch
What is the main function of TOLLEN’S TEST?
To differentiate reducing sugars from non-reducing sugars
Which test is highly specific for detecting galactose and lactose?
MUCID ACID TEST
What distinguishes the OSAZONE TEST from other tests mentioned?
Shape of crystals formed
Study Notes
Carbohydrate Tests
- Molisch test: used to detect the presence of carbohydrates in a sample, involving the addition of Molisch's reagent and concentrated H2SO4, resulting in a purple or purplish-red ring at the point of contact.
Reducing Sugar Tests
- Benedict's test: used to detect the presence of reducing sugars, involving Benedict's reagent, resulting in a brick-red precipitate.
- Fehling's test: used to detect and estimate reducing sugars, consisting of Fehling's A and Fehling's B.
- Tollen's test: used to differentiate reducing sugars from non-reducing sugars, involving the alkaline solution of silver nitrate and liquid ammonia, resulting in a dark grey precipitate or silver mirror.
Monosaccharide Tests
- Barfoed's test: used to detect the presence of reducing monosaccharides in the presence of disaccharides, involving Barfoed's reagent, resulting in a red precipitate.
- Bial's test: used to detect the presence of pentoses, involving orcinol, hydrochloric acid, and ferric chloride, resulting in a blue-green or bluish precipitate.
- Mucic acid test: used to detect the presence of galactose and lactose, involving the formation of saccharic acids, resulting in crystal formation.
Sugar Classification Tests
- Seliwanoff's test: used to differentiate between ketose and aldose sugars, involving resorcinol and concentrated HCl, resulting in a cherry red-colored complex.
- Osazone test: used to detect and classify reducing sugars, involving phenylhydrazine in acetate buffer, resulting in yellow-colored crystals of characteristic shape, solubility, melting point, and time of formation.
Polysaccharide Tests
- Iodine test: used to distinguish mono- or disaccharides from certain polysaccharides like amylase, dextrin, and glycogen, involving Lugol's iodine, resulting in a blue-black or purple color.
Learn about Molisch test, which detects the presence of carbohydrates through the formation of a purple ring, and Benedict's test, which indicates the presence of reducing sugars by the formation of a color change. Understand the procedures and significance of these tests in carbohydrate analysis.
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