Distinguish Test

Question 1

Alkene @bromine

Describe the rest and results

Answer 1

1. Bromine dissolved in CCl4
   - > orange-red bromine decolourised
2. Aq. Bromine
   - > orange bromine decolourised

Question 2

Alkene @KMnO4

Describe the test and results

Answer 2

1. KMnO4 (aq), NaOH(aq), cold
   - > purple KMnO4 decolourised; brown pot MnO2 formed
2. c. KMnO4, H2SO4(aq), warm
   - > purple KMnO4 decolourised, light link Mn2+ sol formed

Question 3

Halogenoalkane

Answer 3

NaOH(aq) heat, cool, acidify with HNO3(aq), follow by AgNO3(aq)

• > white ppt: chloroalkane
• > cream ppt: bromoalkane
• > yellow ppt: iodoalkane

RX + NaOH -> ROH + Na+ + X-
Ag+ + X- -> AgX(s)

Question 4

Alcohol@ Na

Answer 4

Na metal

-> eff pxed. Gas evolved “pops” with a lighted splint

Question 5

Alcohol @anhyd. PCl5, SOCl2

Answer 5

-> white fumes of HCl evolved

Question 6

Alcohol @ strong O.A

Answer 6

1. KMnO4(aq) + NaOH(aq), warm
   - > purple KMnO4 decolourised, brown ppt Mn2+ formed
2. c.KMnO4, H2SO4(aq), warm
   - > purple KMnO4 decolourised, colourless sol Mn2+ formed
3. K2Cr2O7(aq), H2SO4(aq), warm
   - > orange K2Cr2O7 turns green

Question 7

Phenol and phenolic cmpd

3 ways

Answer 7

1. neutral FeCl3(aq)
   - > violet/ purple colouration formed
2. Aq. Bromine
   - > orange bromine decolourised, white ppt of 2,4,6-tribromophenol formed
3. Half spatula of Mg powder/ small piece of Na metal
   - > eff pxed. Gas evolved “pops” with a lighted splint

Question 8

Alcohol/ carbonyl

         OH
          |
     R-C-CH3
          |
         H

     O
     ||
 R-C-CH3

Answer 8

@tri-iodomethane test

A few drops of NaOH(aq), follow by a few drops of I2(aq), warm

-> yellow ppt of CHI formed

Question 9

Carbonyl cmpd

Answer 9

@2,4-DNPH

-> yellow/ orange ppt formed

Question 10

Tollens’ reagent?

Answer 10

Aldehyde
A sol of AgNo3(aq) in Xs NH3(aq), warm

-> silver minor/ grey ppt formed

Question 11

Fehling’s reagent?

Answer 11

Alphatic aldehyde

Alkaline sol of Cu2+ and tartrate ion, warm

-> reddish-brown ppt of Cu2O formed

Question 12

Aldehyde @strong O.A

Answer 12

1. KMnO4(aq), NaOH(aq), warm
   - > purple KMnO4 decolourised, brown ppt MnO2 formed
2. c.KMnO4, H2SO4(aq), warm
   - > purple KMnO4 decolourised, colourless sol Mn2+ formed
3. K2Cr2O7(aq), acidified with H2SO4, warm
   - > orange K2Cr2O7 turns green

Question 13

2 ways for carboxylic acid

Answer 13

1. Na2CO3(aq/s)/ NaHCO3(aq/s)
   - >eff pxed. Gas evolved gives a white pot in limewater
2. small spatula of Mg powder/ small piece Na
   - > eff pxed. Gas evolved “pops” with a lighted splint

Question 14

Acid chloride

Answer 14

AgNO3(aq)

-> while fumes of HCl evolved, white ppt of AgCl formed

Question 15

Ester

Answer 15

Dilute mineral acid, reflux;

Carry our distinguishing test in distillate for alcohol

Question 16

Primary amide

Answer 16

NaOH(aq)

-> gas evolved turned moist red litmus paper blue evolved (NH3)

Question 17

Phenylamine

Answer 17

Aq. Bromine

-> orange bromine decolourised, white ppt of 2,4,6-tribromophenylamine formed

Question 18

Aq Br2 can be used for?

Answer 18

1. Alkene
2. Phenol
3. Phenylamine

Question 19

2,4-DNPH for?

Answer 19

Carbonyl cmpd

• aldehyde
• ketone

Question 20

K2Cr2O7

Answer 20

• alcohol (1,2)

- aldehyde

Question 21

Strong OA (KMnO4), heat

Answer 21

Alkene
Methylbenzene
Alcohol(1,2)
Aldehydes

Question 22

Strong OA (KMnO4) cold

Answer 22

Alkene

Question 23

PCl5, PCl3, SOCl2, PBr3

Answer 23

All alcohols

Question 24

Na(s)

Answer 24

All alcohol, phenol, RCOOH

Question 25

Mg(s)

Answer 25

Phenol, RCOOH

Question 26

Na2CO3

NaHCO3

Answer 26

RCOOH

Acid chlorides