Test For Molecules

Question 1

Starch

Answer 1

Iodine

Brown to blue black

Question 2

Reducing sugars (mono & disaccharides)

Answer 2

Benedict’s solution + heat

Blue to red

Question 3

Non-reducing sugars (sucrose)

Answer 3

Boil with HCl (sucrose to glucose and fructose
Neutralise with NaOH
Test for reducing sugars

Question 4

Lipids

Answer 4

Soapy water or ethanal

White emulsion

Question 5

Proteins

Answer 5

Buret

Blue to lilac

Question 6

What compounds in solution

Answer 6

Chromatography
Stationary phase
-TLC plate
Mobile phase
-Water or ethanol

Question 7

Quantative test or reducing sugars

Answer 7

Benedict’s
- more reducing sugars = more precipitate = less blue solution
Calibrate calorimeter using known concentration for light transmission
Then test unknown sample

Set colour to