Distinguishing Tests

Question 1

Halogenoalkanes

Answer 1

Ethanolic AgNO3 and heat
Chloro: white, soluble in aq NH3
Bromo: cream, partially soluble in aq NH3
iodo: yellow; insoluble in aq NH3

Question 2

Acyl chloride

Answer 2

Ethanolic AgNO3 w/o heat
White ppt formed immediately without heating
Na2CO3/NaHCO3 (aq): react with water to form Carboxylic acid then Carboxylic acid react with carbonate to give CO2

Question 3

Phenol (3 ways)

Answer 3

Neutral FeCl3 : violet colour observed
Br2 (aq) decolorise and white ppt formed
Na metal: effervescence observed test for h2

Question 4

Aldehyde/ketone (6 ways)

Answer 4

2-4 DNPH: Orange ppt for aldehyde and ketone
Tollens: silver mirror formed for all aldehyde
Fehling: all aliphatic aldehydes give reddish brown ppt Cu2O
Aq I2 with aq NaOH and heat: aldehyde and ketone with -COCH3 structure, yellow ppt is CHI3
Kr2Cr2O7(aq), H2SO4(aq) heat: orange turns green for all aldehydes
KMnO4, H2SO4 heat: aldehyde, purple KMnO4 decolorise

Question 5

Carboxylic acid (3ways)

Answer 5

Na2CO3/NaHCO3: effervescence prod, test for CO2 gas
Na metal: effervescence h2
PCl5: dense white fumes of Hcl

Question 6

Alcohols (5ways)

Answer 6

Iodofoam: yellow CHI3 ppt formed for alcohols with -C(OH)CH3 structure
Na Metal: effervescence H2 (test)
PCl5: dense white fumes of Hcl
K2cr2o7 (aq) h2so4(aq) heat: orange k2cr2o7 turns green
KMnO4 h2so4 heat: purple KMnO4 decolorise

Question 7

Alkene (2 ways)

Answer 7

Orange Br2 decolorise

KMnO4 h2so4 heat: purple KMnO4 decolorise + gas co2 for Alkene with terminal carbon

Question 8

Phenyl amine

Answer 8

Orange Br2 decolorise