Starch

Starch

Structure

• Insoluble with water
• Insoluble with 30% NaOH
• Insoluble with dil.HCl
• L.P: Neutral

Procedure:

Physical Characters

Thanks for your attention

Done by:

Mohammed Attia

n

[C6H12O5]

n

Condition

Colour

Odour

Solid, Powder

Odourless

White

Solubility

General Class Reaction:

1- Molish's test: Violet ring.

Add 2ml unk soln

+2dps Alc.alpha.Naphthol

+dps wise of Conc.H2SO4 (till formation of violet ring)

2- Barfoed's reagent: No red spots.

3- Tollen's test: No silver mirror.

-On cold:No action

-On Hot: Burned sugar odour

4- Fehling's test: No red to brown ppt

Add 1.5gm phenyl hydrazine

+ 0.5gm Na acetate

+ 0.5gm suger

+ 8ml water

W.B

20 min

5- Osazone test: No Yellow ppt on boiling or after cooling

• Action of Sodalime (CaO+NaOH):

-On cold: No action

-On Hot: Gel formation

Special test:

Add 2ml suspension

+ 2dps Iodine

Add 2ml unk suspension

W.B

1- Iodine test: Blue color

2- Boiling with water: Gel formstion

Change to Glucose

Iodine

W.B

15min

No Blue color

Starch suspension + Conc.HCl

• Action of 30% sodium hydroxide:

3- Hydrolysis test: No Blue color

No action

• Action of ferric chloride:

-On cold: Darkening

-On Hot: Blackening & Eff & evolution of CO and CO2

• Action of Conc.Sulphuric: