6. Hydroxyl Compounds

Question 1

can alcohol undergo oxidation?

Answer 1

yes.

Question 2

reagents and conditions for oxidation of primary alcohol to aldehyde

Answer 2

K2Cr2O7, dilute H2SO4, heat with immediate distillation

Question 3

reagents and conditions for oxidation of primary alcohol to carboxylic acid

Answer 3

KMnO4/K2Cr2O7, dilute H2SO4, heat

Question 4

can alcohol be reduced?

Answer 4

no. a reduction of the O means addition of H to the O which is already present.

Question 5

reagents and conditions for dehydration of alcohol & state the end product

Answer 5

excess conc. H2SO4, heat.
alkene.

Question 6

reagents and conditions of alcohol for nucleophilic substitution of halogen [3]

Answer 6

1. PCl3, heat
2. PCl5
3. SOCl2

Question 7

alcohol reacts with ___ to form ester

Answer 7

carboxylic acid / acyl chloride

Question 8

is alcohol an acid?

Answer 8

yes. as it loses H so it can undergo acid reactions except with NaOH

Question 9

describe the criteria that the alcohol needs to have for a positive iodoform test

Answer 9

alcohol needs to have a methyl group, a H atom bonded directly to the C-OH

Question 10

is phenol or alcohol a stronger acid? why?

Answer 10

phenol.
- stronger acid = greater ease of H dissociation = less H attraction to O
- in phenols, the lone pair on O delocalises into the benzene so the O becomes less -ve

Question 11

phenol reacts with carboxylic acids to form esters. T/F

Answer 11

False.
when reacting with COOH, phenol is a very weak Nu- due to delocalisation of lone pair into the benzene ring, hence the C on COOH is unable to attack the phenol.

Question 12

phenol reacts with acyl chlorides to form esters. T/F

Answer 12

True.
acyl chlorides are more reactive than COOH. To make the process more efficient, NaOH is added to phenol to form phenoxide ion (anion thus stronger Nu-)