Organic Tests

Question 1

Alkene

Answer 1

Test: Add bromine water drop-wise
Observation: Bromine water decolourised from orange to colourless.

Question 2

Haloalkane

Answer 2

Test: Add Silver Nitrate and ethanol and warm to 50 degrees in a water bath.
Observation: Cl - white ppt. Br - Cream ppt. I - Yellow ppt.

Question 3

Carbonyl

Answer 3

Test: Add 2,4 - dinitrophenylhydrazine (2,4 - DNP)
Observation: Orange ppt,

Question 4

Aldehyde

Answer 4

1. K2Cr2O7/H+ Green ppt
2. Tollens’ reagent [Ag(NH3)2]+ Silver mirror
3. Fehling’s solution [Cu2+ to Cu+] Orange ppt

Question 5

Primary and Secondary Alcohol

Answer 5

Test: Adde acidified potassium dichromate (VI) and warm in a water bath.
Observation: Colour change from orange to green.

Question 6

Carboxylic Acid

Answer 6

1. Aqueous sodium carbonate Effervescence

2. Damp litmus paper Red colour