Topic 6 Halogenoalkanes and Alcohols

Question 1

What is the reagent and conditions to produce an alkene from a halogenoalkane.

Answer 1

Warm ethanolic NaOH carried out under reflux.

Question 2

What is the reagent and reason to use this reagent with halogenoalkanes to make triple bond N

Answer 2

Warm ethanolic potassium cyanide
Increases number of carbon atoms in the chain.

Question 3

Why are things heated in a sealed container?

Answer 3

Heating increases rate of reaction and no sealed tube would lose gas.

Question 4

Which bond takes longest to form precipitate?

Answer 4

Chloro

Question 5

Why would you add ethanol in a silver nitrate test for halogenoalkanes?

Answer 5

Dissolves the halogenoalkane

Question 6

Why are halide ions present in mixture when silver nitrate is done?

Answer 6

Halogenoalkane hydrolysed by water
C-Hal bond breaks therefore ions present.

Question 7

An experiment that enable hydrolysis rates of halogenoalkanes to be compared

Answer 7

Ethanol as solvent
Use silver nitrate
Equal amounts halogenoalkane
Measure time taken
Water bath control raised temp
Jodo fastest - lowest bond enthalpy

Question 8

What are stereoisomers?

Answer 8

Compounds that have the same structural formula but atoms have different arrangement in 3D space.

Question 9

Z

Answer 9

Same side

Question 10

E

Answer 10

Opposite

Question 11

Chemical test positive result for alcohol but not carboxylic acid.

Answer 11

Bromine water goes colourless

Question 12

What colour precipitate for iodine?

Answer 12

Yellow

Question 13

Conditions to form alcohol from halogenoalkane

Answer 13

Warm aq NaOH

Question 14

What conditions when reacting with ammonia - halogenoalkane.

Answer 14

Excess ethanolic ammonia

Question 15

What else is made when you react halogenoalkane with ammonia

Answer 15

Amine (fishy smell)

Question 16

What type of alcohol reacts fastest with HCl.

Answer 16

Tertiary

Question 17

What reactants can you use to make a chloroalkane from an alcohol

Answer 17

HCl
PCl5

Question 18

Conditions for making Bromoalkane from alcohol

Answer 18

NaBr
50% acid catalyst
H2SO4

Question 19

Reagent for making iodoalkane from alcohol

Answer 19

Phosphorus triiodide

Question 20

What happens during dehydration of an alcohol?

Answer 20

Water eliminated
Acid catalyst used H2SO4 or H3PO4
Forms alkene plus water

Question 21

What reagent can alcohols be oxidised by

Answer 21

Potassium dichromate

Question 22

Testing for aldehydes and ketones

Answer 22

Fehlings solution
Blue -> brick red for aldehydes because it is an oxidising agent

Question 23

What does potassium dichromate change colours from and to?

Answer 23

Orange to green (Cr3+)