LAB ACTIVITY 2 QUALITATIVE TESTS FOR CARBOHYDRATES

Barfoed’s test is used to distinguish _______________________.

• Reducing from non-reducing sugars

• Monosaccharides from disaccharides

• Ketoses from aldoses

• The solubility of carbohydrates

Which result indicates a positive Molisch test?

• A red precipitate forms

• A purple or violet ring at the interface

• A colorless solution remains

• Gas bubbles evolve rapidly

What does Fehling’s test detect?

• reducing sugars

• carbohydrates in general

• ketoses

• aldoses

What is observed in a positive Fehling’s test?

• No visible change occurs

• A purple solution forms

• A red or orange precipitate forms

• A green solution forms

What is the Molisch test primarily used to detect?

• reducing sugars

• carbohydrates in general

• ketoses

• aldoses

What indicates a positive Tollens' test?

• A silver mirror forms on the test tube

• A purple ring at the interface

• The solution becomes clear

• A blue precipitate forms

Which color indicates a positive result in Seliwanoff’s test?

• Blue or green

• Red or deep pink

• Purple or violet

• Colorless solution remains

Tollens' test is primarily used to identify _______________.

• Non-reducing sugars

• Reducing sugars and aldehydes

• Ketoses in carbohydrates

• The solubility of a carbohydrate

Which observation indicates a positive result in Barfoed’s test?

• A red precipitate forms within 1-2 minutes

• A greenish solution develops

• A purple ring forms at the interface

• The solution remains unchanged

Seliwanoff’s test is used to distinguish ______________.

• keto and reducing sugars

• aldo and non-reducing sugars

• reducing and non-reducing sugars

• keto and aldo sugars