Tests for Carbohydrates

Q. The brick red precipitate formed in Fehling's and Benedict's test is due to the

1. Reduction of Cu²⁺ ions to Cu⁺ ions

2. Formation of Cu(I)oxide

3. Presence of sulphur ions in the reagents

4. Presence of non-reducing sugars

Q. Which one of these is a reducing sugar ?

1. Galactose
2. Gluconic acid
3. Sucrose
4. $\beta$ -methylgalactoside.

Q.

Why is glucose a 'reducing sugar'?

1. it has a ketone group

2. it contains an aldehyde group

3. it is a monosaccharide

4. glucose is not a reducing sugar

Q. Fehling's test is not positive in case of _________.

1. Lactose
2. Sucrose
3. Glucose
4. Fructose

Q. Molisch's test is done for the detection of ________.

1. Alkyl halide
2. Carbohydrate
3. Alkaloid
4. Fat