Carboxyls

Question 0

How are carboxylic acids produced from 1bromoethane? (2 ways)

Answer 0

1)NS of KCN in ethanol
Then acid hydrolysis of nitrile formed

2) NS to an alcohol with NaOH(aq) h/r
Then oxidation using Cr2O72-/H+ conc/aq h/r

Question 1

What 5 ways are there of producing carboxylic acids?

Answer 1

• Oxidation of primary alcohols
• Hydrolysis of Acyl Chlorides
• Alkaline hydrolysis of nitriles
• Acid hydrolysis of nitriles
• Alkaline hydrolysis of an ester

Question 2

What is formed when an acyl chloride is hydrolysed using water?

Answer 2

Carboxylic acid + HCl

Question 3

What is the test to confirm that a nitrile has been converted to a carboxylsalt via alkaline hydrolysis?

Answer 3

NH3 is produced so blue litmus turns red

Question 4

How do you convert a nitrile to a carboxylic acid?

Answer 4

Either
a) alkaline hydrolysis using NaOH(aq) h/r then acidify using HCl
Or
b) acid hydrolysis using HCl (aq) h/r

Question 5

How are carboxylic acids decarboxylated?

Answer 5

By heating with soda lime

Forms an alkane with -1C chain

Question 6

What are the conditions for the halogenation of carboxylic acids?

Answer 6

PCl5 anhydrous room temp

Question 7

What is formed from the halogenation of carboxylic acids?

Answer 7

Acyl chlorides

Question 8

What are the conditions needed to convert an acyl chloride to an amide?

Answer 8

NH3 conc
Anhydrous
Room temp

Question 9

What happens when carboxylic acids are reacted with (NH4)2CO3 with heat?

Answer 9

An acid-base reaction

RCOO-NH4+ + CO2 + H2O

Question 10

How can the ammonium salt of a carboxylic acids be converted to an amide?

Answer 10

Heat strongly with P4O10

Question 11

Why are carboxylic acid’s oate ions relatively stable?

Answer 11

The negative charge can be delocalised across several atoms

R-COO-

Question 12

Why is methanoic acid more acidic than ethanoic acid?

Answer 12

Methanoic acid readily delocalises due to no induction by H
(The O withdraws and O-H bond is weakened)
Ethanoic acid is influenced by the inductive alkyl group (+ve inductive effect) so there is increased stability of the starting materials

Question 13

How is a benzene carboxylic acid formed?

Answer 13

Methyl benzene —MnO4-/ OH-
Na2CO3(aq) —> phenyl carboxyl salt + 6H+ + 6e-
Then acidify with HCl (aq) to form phenyl carboxylic acid

Question 14

How can the sodium salt of benzene carboxylic acid be decarboxylated?

Answer 14

Using NaOH(s)
Forming benzene + Na2CO3