Organic Tests and reaction

Question 1

Test for phenolic compounds / phenol

Answer 1

Add aqueous iron III chloride-

Purple colour or solution present

Question 2

Test for a carboxylic acid

Answer 2

Add sodium carbonate

Fizzing seen with co2 (bubbles))

Question 3

Test for an alcohol

Answer 3

I2/ NaOH (aq)
CH3CHOH group
Yellow PPT
Antiseptic smell

Question 4

Test for an aldehyde x2

Answer 4

Tollens (AgNO3/NH3 complex)
Silver mirror result

Fehlings (CuSO4 complex) - blue to red colour change result

Both redox

Question 5

Test for aldehydes and ketones

Answer 5

24DNP- orange crystals with high melting points (NUCLEOPHILIC addition/elimination)

I2/NaOH A -CH3CO group yellow ppt anti septic smell

Question 6

Distinguishing between aliphatic and aromatic amines

Answer 6

1- add nitrous acid to both in cold conditions
Bubbles nitrogen gas seen with aliphatic, no bubbles with aromatic

2- add nitrous acid to both in cold alkaline conditions, add an aromatic compound eg phenol. A colour is produced with aromatic, no colour with aliphatic

Question 7

Identifying an ester

Answer 7

Hydrolysis reaction- forms a carboxylic acid (and alcohol) in the form of a colourless solution (aliphatic ester) or White PPT (aromatic )

Question 8

Identifying a basic compound

Answer 8

Red litmus paper- turns blue

Question 9

Identifying an acidic compound

Answer 9

Turns blue litmus paper red

Question 10

Identifying an amide or nitrile

Answer 10

Alkane hydrolysis- produce ammonia NH3 gas that turns red litmus blue

Question 11

Distinguishing between aromatic and aliphatic acids

Answer 11

Their solubility in. Water- aliphatic acids are soluble so produce a colourless soliton (no white ppt)

Aromatic acids produce white ppt (insoluble/sparingly)

Question 12

Nitrating benzene

Answer 12

Concentrated sulfuric and nitric acid 55degrees

Question 13

Halogenising benzene

Answer 13

No light; room temp: anhydrous

Question 14

Alkylation of benzene

Answer 14

Room temp , anhydrous

Question 15

Delocalisation energy calculation of benzene

Answer 15

Calculate delta H
One is experimental, one is theoretical

The difference between them is the DE

Question 16

If aqueous sodium borohydride is used to reduce Unknown compounds at room temp: what are they going to be?

Answer 16

Aldehydes or ketones because it only reduces these

Question 17

Why is phenol more subseptible to Electrophilic substitution (addition of bromine/bromine water)

Answer 17

Catalyst isn’t required
Conc bromine not required
Mono subsituted product not produced

Question 18

Production of an aromatic ester from phenol

Answer 18

Reaction with ethanoyl chloride - NUCLEOPHILIC substitution

Question 19

Method to identify an aldehyde ketone using DNP

Answer 19

1 add unknown to dnp in dilute acid
2- orange crystals form
3- filter and wash with cold solvent
4- dry and take the MP and compare with literature value

Question 20

Oxidation reactions reagent and observation

Answer 20

Acidification potassium dichromate (aqueous sulfuric acid used)

Orange to green colour change

Not with ketones though as they’re not easily oxidised

Question 21

What is produced in the hydrolysis of acid chlorides

Answer 21

Carboxylic acid

Question 22

Is the sodium salt for benzoicacid soluble?

Answer 22

Yes

Question 23

How do you obtain a carboxylic acid from salt?

Answer 23

Add strong acid

Question 24

How do you isolate a product eg carboxylic acid?

Answer 24

Filter
Wash with cold solvent
Recrystallise from hot water
Dry in oven below MP

Question 25

Converting carboxylic acid to amide

Answer 25

Add ammonium carbonate o acid to produce ammonium salt

Heat salt and this forms an amide

Question 26

Converting carboxylic acid to nitrile

Answer 26

Add ammonium carbonate to acid and produces ammonium salt

Heat salt to form an amide

Add phosphorus V oxide (P4O10) amide dehydrates to form nitrile

Question 27

Converting amide to nitrile

Answer 27

Add phosphorus V oxide (P4O10) and it dehydrates to form nitrile

Question 28

Converting nitrile to carboxylic acid

Answer 28

Hydrolysis - acid – reflux with hydrochloric acid aq and forms a C acid

Question 29

Converting nitrile to amine

Answer 29

Lithium aluminium hydride (reduction) room temp, anhydrous [4H]

Question 30

Converting halogenoalkane to :
Nitrile
Amine

Answer 30

Nitrile- reflux with potassium cyanide in a solution of ethanol (NUCLEOPHILIC sub)

Amine: Heat Halo with excess ammonia in a solution of ethanol
Conducted in a sealed tune immersed in boiling water
NUCLEOPHILIC sub

Question 31

How to form an aromatic amine eg phenylamine?

Answer 31

Heat nitrobenzene with tin and hydrochloric acid - reduction
This forms a soluble salt, then add sodium hydroxide (aq) to form aromatic amine

(Use steam distillation to separate phenylamine from nitroB)

Question 32

Forming an aromatic ester from phenol

Answer 32

Add ethanoyl chloride : of produces ester - NUCLEOPHILIC sub

Question 33

Tests for phenol

Answer 33

1- aqueous iron III chloride
Purple colour seen (OH)

2- bromine / bromine water- White PPT subsitutes 2,,4,6 positions (Electrophilic substitution)

Question 34

Forming an alkene from an alcohol

Answer 34

Dehydration : excess concentrated sulfuric acid, 180degrees and reflux

Question 35

Formation of an alcohol from an alkene

Answer 35

Hydration - phosphoric acid catalyst 300degrees 70atm

Steam