A2 Qualitative Analysis of Carbohydrates (I)

Question 1

Molisch Test

Sucrose
Starch
Dextrin
Glucose
Arabinose

Answer 1

S Purple +
S Purple +
D Purple +
G Purple +
A Purple +

Presence of Carbohydrate

Question 2

Orcinol/Bial’s Test

Glucose
Fructose
Ribose
Galactose
Arabinose

Answer 2

yellow-brown = hexose
blue-green = pentose

G yb
F yb
R yb
G yb
A bg

Question 3

Seliwanoff’s test

Fructose
Glucose
Galactose

Answer 3

Cherry Red = ketohexose
Light pink = aldohexose

F Cherry Red
G Light Pink
G Light Pink

Question 4

Benedict’s Test

Glucose
Fructose
Lactose
Sucrose
Maltose

Answer 4

Brick Red=Reducing

G Brick Red
F Brick Red
L Brick Red
S N/A
M Brick Red

Question 5

Barfoed’s Test

Glucose
Fructose
Lactose
Sucrose
Maltose

Answer 5

Monosaccharide
Disaccharide

G Mono
F Mono
L Di
S N/A
M Di

Question 6

Willa monosaccharide reduce benedict’s reagent?

Answer 6

Yes

Question 7

Is sucrose a reducing sugar?

Answer 7

No

Question 8

Classify the following:

Starch
Dextrin
Gulose
Idose
Mannose

Answer 8

Polysaccharide
Polysaccharide
Monosaccharide
Monosaccharide
Monosaccharide
Monosaccharide

Question 9

Classify the following:

Inulin
Gum-Arabic
Cellulose
Cellobiose
Agar-agar

Answer 9

Polysaccharide
Polysaccharide
Polysaccharide
Disaccharide
Polysaccharide