Organics

Question 1

conditions for free radical substitution (alkanes)

Answer 1

• UV present

Question 2

Reagents to produce a diol

Answer 2

Oxidation of alkenes with COLD, dilute KMnO4 and water

Question 3

Dehydration of alkenes catalyst and condition

• Turning Alcohol into Alkenes and water

Answer 3

Al2O3 + Heat

Question 4

Colour change of KMnO4 when added to alkene

Answer 4

Pale purple –> Colourless

Question 5

Result of reacting Chloroalkanes with Silver Nitrate

Answer 5

White PPT

Question 6

Result of reacting Bromoalkanes with Silver Nitrate

Answer 6

Cream PPT

Question 7

Result of reacting Iodoalkanes with Silver Nitrate

Answer 7

Yellow PPT

Question 8

Rank the reactivity of haloalkanes in order from the most reactive

Answer 8

Iodoalkane
bromoalkane
chloroalkane
fluoroalkane

Question 9

observation of sodium reacting with alcohol

Answer 9

White solid of sodium alkoxide formed

Question 10

Colour change of K2Cr2O7 in oxidation of alcohols

Answer 10

Orange –> Green

Question 11

Colour change of KMnO4 in oxidation of alcohols.

Answer 11

Purple –> Colourless

Question 12

What is the iodoform test used to detect

Answer 12

Methyl ketones
Secondary alcohols

Question 13

What is the positive result of the iodoform test

Answer 13

A yellow ppt of triiodomethane

Question 14

WHich reagents are used in the iodoform test

Answer 14

Iodine in an alkaline solution (NaOH)

Question 15

What are the two steps in the iodoform reaction

Answer 15

• Halogenation: All three H atoms in methyl group are replace with iodine atoms forming Cl3 group
• Intermediate compound is hydrolysed which forms a sodium salt and a yellow ppt

Question 16

catalyst and condition in hydrogenation of alkenes

Answer 16

Pt/Ni
Heat

Question 17

Catalyst and condition in hydration of alkenes

Answer 17

H3PO4
Heat

Question 18

Two oxidising agents to oxidise alkene

Answer 18

Hot concentrated KMnO4 and cold dilute KMnO4

Question 19

Three ways of product for oxidation of alkene with hot KMnO4

Answer 19

Carbon bonded to 2 hydrogens: Alkene —> CO2

Carbon bonded to 1 hydrogen, 1 Alkyl group:
Aldehyde –> Carboxylic acid if aldehyde not distillated out imeediately

Carbon bonded to 2 alkyl group:
Ketone

Question 20

What reagent is used to test for aldehyde and ketones

Answer 20

2,4 DNPH

Question 21

What is the positive result when 2,4-DNPH reacts with a carbonul compound

Answer 21

Forms a deep orange precipitate

Question 22

How do you know specifically which aldehyde or ketone be determined after 2,4-DHPH testing

Answer 22

Recrystallise the ppt and compare its melting point ot known values

Question 23

Which carbonyls do not react with 2,4-DNPH

Answer 23

Carboxylic acids and esters

Question 24

What is used to distinguish aldehydes from ketone

Answer 24

Fehling’s solution and Tollen’s reagent

Question 25

What happens when an aldehyde reacts with Fehling's solution

Answer 25

clear blue solution forms a red ppt

Question 26

What is the result when a ketone is tested with Fehling's solution

Answer 26

No Reaction

Question 27

What is thje visible result of an aldehyde reacting with Tollen's Reagent

Answer 27

A silve rmirror forms on the test tube

Question 28

What happens when ketone is tested with Tollen's Reagent

Answer 28

No reaction

Question 29

Test for carboxyl functional group

Answer 29

Add Na2CO3, gas of CO2 will be produced.