Organic Chemistry Test

Question 1

1) warm with acidified potassium
dichromate(VI)
2) orange to green
solution

Answer 1

Primary alcohol or Secondary alcohol or aldehyde

Question 2

shake with bromine water

1) colourless
2) white precipitate

Answer 2

1) alkene

2) phenol

Question 3

warm with aqueous
sodium/potassium hydroxide, acidify
with dilute nitric acid then add
aqueous silver nitrate

1) white
2) creamy
3) yellow

Answer 3

Halogenoalkanes:

1) C-Cl
2) C-Br
3) C-1

Question 4

phosphorus(V) chloride

1) Steamy fumes of HCL that turn litmus paper red

Answer 4

OH group in alcohols and carboxylic acids

Question 5

2,4−dinitrophenylhydrazine solution

1) orange percepiate

Answer 5

C=O group in aldehydes and ketones

Question 6

Boil with Fehiling’s or Benedicts solution

1) blue solution gave a red precipitate

Answer 6

Aldehyde

Question 7

warm with ammoniacal silver nitrate
(Tollens’ reagent)

1) silver mirror

Answer 7

Aldehyde

Question 8

sodium or potassium carbonate or
hydrogencarbonate solution

1) effervescence

Answer 8

Carboxylic acid

Question 9

add a small piece of sodium

1)effervescence
(bubbles), sodium
dissolves, white
solid formed

Answer 9

Alcohol
Phenol
Carboxylic acid

Question 10

warm with carboxylic acid and a few
drops of concentrated sulfuric acid

1)ester smell, eg
glue-like

Answer 10

Alcohol

Question 11

sodium nitrite and dilute hydrochloric
acid followed by an alkaline solution
of phenol in ice-cold conditions

1) Orange precipitate

Answer 11

Aromatic Amine

Question 12

iodine in alkaline solution

1) pale yellow precipitate

Answer 12

Methyl ketone or ethanal

Methyl secondary alcohol or ethanol.