Carboxylic Acid And Ester

Question 1

What happens when carboxylic acids react with water

Answer 1

They partially dissociate and a carboxylate salt forms

Question 2

What happens when carboxylic acids react with sodium hydroxide and give the equation

Answer 2

A sodium salt and water is produced

R-Cooh +Naoh-> R-COO-NA+ +H2O

Question 3

What happens when carboxylic acids react with sodium carbonate and give the equation

Answer 3

A sodium salt is produced Co2 and water

2R-COOH(aq)+Na2CO3(aq)->2R-COO-Na+ CO2+H20

Question 4

How are carboxylate salts converted back into carboxylic acids

Answer 4

By reacting then with an acid HCL

R-COO- +H2O==R-COOH + OH-

Question 5

What is the reaction called when carboxylic acid and alcohols react and give the conditions for the reaction and the products

Answer 5

Esterification

Heat under reflux with concentrated H2SO4

Carboxylic acid+alcohol==R-COOR2+H2O

Question 6

What is estrification an example for

Answer 6

A condensation reaction

Question 7

What are the 3 things esters can be used for

Answer 7

They can be used a food flavourings as they have a nice smell

Plasticizers-they are added to polymers to make them less rigid and more flexible by weakening the intermolecular forces between polymer chains

Esters are used as solvents

Question 8

What is the reaction called when an esterification is reversed

Answer 8

Ester hydrolysis

Question 9

Give the conditions and products formed from ester hydrolysis and the equation

Answer 9

Heat under reflux with concentrated H2SO4

A carboxylic acid and alcohol are produced

R1-COOR2+H2O==R1-COOH+R2OH

Question 10

What is the issue with ester hydrolysis

Answer 10

It doesn’t undergo completion,and dosent give a very good yield or carboxylic acid or alcohol

Question 11

What is the reaction called when an ester is heated under reflux with NAOH

Answer 11

Saponification

Question 12

What is produced in saponification

Answer 12

R1-COOR2+NAOH==R1-COO-Na+ + R2OH

A carboxylate salt and alcohol

Question 13

Why is saponification better that ester hydrolysis

Answer 13

It’s not readily reversible,so it produces a better yield of alcohol and carboxylate

Question 14

In saponification how is the carboxylate converted into carboxylic acid

Answer 14

By reacting it with an acid

RCOO+H+=R-COOH

Question 15

In acid hydrolysis of fats and oils what are the products that are produced

Answer 15

Glycerol and 3 fatty acids

Question 16

What is the use of glycerol and 3 fatty acid molecules

Answer 16

Glycerol is used by the body to make glucose for respiration

Fatty acids used to make cell membranes

Question 17

When fats and oils are hydrolysed commercially in alkaline conditions what is produced

Answer 17

Glycerol and salts of fatty acids

Question 18

In saponification what is the glycerol produced used for

Answer 18

It’s used in cosmetics and pharmaceuticals

Question 19

What are the salts of the fatty acids used for and why are they useful

Answer 19

As soaps

Which have a polar end which attracts water and other hydrophilic groups and a non polar end which attracts oils and hydrophobic groups which allows them to mix

Question 20

What are biodiesels made out of

Answer 20

Methyl esters of long chain fatty acids

Question 21

How are biodiesels made and give the reaction name

Answer 21

By fate and oils being reacted with methanol

Known as transectrification reaction