carboxylic acids and derivatives

Question 1

What functional group characterizes carboxylic acids?

Answer 1

COOH functional group

Question 2

Are carboxylic acids strong or weak acids?

Answer 2

Weak acids

Question 3

What ions do carboxylic acids dissociate into in water?

Answer 3

Carboxylate ion and H+ ion

Question 4

What physical property allows carboxylic acids to be soluble in water?

Answer 4

Ability to form hydrogen bonds

Question 5

What happens to the solubility of carboxylic acids as chain length increases?

Answer 5

Solubility rapidly reduces

Question 6

What is the reason for the high melting point of carboxylic acids?

Answer 6

They form hydrogen bonds with one another

Question 7

How can carboxylic acids be identified?

Answer 7

By measuring melting point and comparing with known tables

Question 8

What is the effect of the polarization of the carboxylic acid group?

Answer 8

It is open to attack from nucleophiles

Question 9

What occurs when the hydrogen of the -OH group in a carboxylic acid is lost?

Answer 9

A carboxylate ion is formed

Question 10

What is the stability of the carboxylate ion attributed to?

Answer 10

Negative charge is shared over the whole carboxylate group

Question 11

What is the reaction of a carboxylic acid with a metal?

Answer 11

Carboxylic acid + metal → salt + hydrogen

Question 12

What is produced when a carboxylic acid reacts with a carbonate?

Answer 12

Salt + water + carbon dioxide

Question 13

What is the product of the reaction between a carboxylic acid and a metal hydroxide?

Answer 13

Salt + water

Question 14

What is formed when a carboxylic acid reacts with ammonia?

Answer 14

Ammonium salt

Question 15

What is esterification?

Answer 15

Carboxylic acid + alcohol ⇌ ester + water

Question 16

What catalyst is typically used in esterification?

Answer 16

Strong concentrated H2SO4

Question 17

What is the general reaction for acid hydrolysis of an ester?

Answer 17

Ester + water ⇌ carboxylic acid + alcohol

Question 18

What is the product of base hydrolysis of an ester?

Answer 18

Salt of carboxylic acid + alcohol

Question 19

What is the general formula for lipids?

Answer 19

3 fatty acids + 1 glycerol

Question 20

What happens during lipid saponification?

Answer 20

Lipid + 3KOH → 3 salts of fatty acids (soap) + glycerol

Question 21

What is produced when a lipid reacts with methanol?

Answer 21

3 methyl esters of fatty acids + glycerol

Question 22

What are some uses of esters?

Answer 22

• Sweet smell in perfumes
• Flavoring in drinks/sweets
• Solvents in glues and inks
• Plasticizers in polymerization

Question 23

What are acyl chlorides?

Answer 23

Derivatives of carboxylic acids by substitution of the -OH group with a chlorine atom

Question 24

What is the process by which the acyl group is introduced into another molecule?

Answer 24

Acylation

Question 25

What factors affect the reactivity of acylation?

Answer 25

* Magnitude of delta+ charge on carbonyl carbon * Ease of leaving group loss * Quality of nucleophile

Question 26

What products result from acylation reactions with acyl chlorides or acid anhydrides?

Answer 26

* Carboxylic acid with water * Ester with alcohol * Amide with ammonia * N-substituted amide with primary amine

Question 27

What toxic byproduct is always produced when acyl chlorides react?

Answer 27

HCl

Question 28

What is the advantage of using ethanoic anhydride over ethanoyl chloride in the synthesis of aspirin?

Answer 28

Cheaper, less corrosive, less vulnerable to hydrolysis, less dangerous

Question 29

What is the equation for the formation of aspirin?

Answer 29

2-hydroxybenzoic acid + ethanoic anhydride → aspirin + ethanoic acid