Alcohols Module 4

Question 1

What’s the general formula for an alcohol?

Answer 1

CnH(2n+1)OH

Question 2

What’s a primary alcohol?

Answer 2

OH group is attached to a Carbon which is bonded to only 1 other Carbon

Question 3

What’s a secondary alcohol?

Answer 3

OH group is attached to a Carbon which is attached to 2 other Carbons

Question 4

What’s a tertiary alcohol?

Answer 4

OH group is attached to a Carbon which is attached to 3 other Carbons

Question 5

Why are alcohols generally polar molecules?

Answer 5

Due to electronegative OH group which pulls electrons away from C atom, making the C and H delta positive, and the O delta negative

Can form hydrogen bonds

Question 6

What does Hydrogen bonding make happen in alcohols?

Answer 6

If mixed In water will be soluble, due to interactions between OH and H2O, however the bigger the alcohol, the more of it’s non polar so solubility increases

Alcohols have higher melting points as can hydrogen bond with each other, which is the strongest intermolecular force

Question 7

what can OH be swapped for to produce a Haloalkane, and what catalyst is required?

Answer 7

halogen in a substitution reaction

acid catalyst

Question 8

what can be done to alcohols to form alekenes?

Answer 8

can be dehydrated, in a elimiation reaction

Question 9

what happens to an alcohol during an elimination reaction?

Answer 9

with sulfuric acid or phosphoric acid catalyst, and heat

alcohol goes to an alkene+water

be aware E/Z isomers can form

Question 10

what colour does ethanol burn with?

Answer 10

pale blue

Question 11

what’s the easiest way to oxidise an alcohol?

Answer 11

burn in oxygen, forms CO2 and Hydrogen

Question 12

how can you oxidise primary alcohols, and what are the possible products?

Answer 12

To form an aldehyde (last carbon double bonded to an O, and also single bonded to H)

use Oxidiaing agent (acidified dichromate)

heat and distil to form aldehyde

then heat under reflux this aldehyde with more oxidising agent to form a carboxylic acid (final carbn double bonded to an O, and also bonded an OH group)

Question 13

What do you get if you oxidise a secondary alcohol and how do you do it?

Answer 13

heat under reflux with acidified dichromate

produces a ketone (middle carbon double bonded to Oxygen)

Question 14

can tertiary alcohols be oxidised?

Answer 14

no, can only be burned