Carbonyl compounds

Question 1

What is a carbonyl group?

Answer 1

A carbon-oxygen double bond

Question 2

What compounds is a cabonyl group found in?

Answer 2

Aldehyde and ketones

Question 3

What is the relative charge o the carbon of a carbonyl group?

Answer 3

+

Question 4

What feature of a carbonyl group makes it susceptible to attack from nucleophiles?

Answer 4

The polarity of the double bond.

Question 5

What are the typical reactions of carbonyl compounds?

Answer 5

Nucleophilic addition

Question 6

What happens ina nucleophilic addition reaction?

Answer 6

The nucleophile adds onto the C^d+ and a hydrogen adds on to the O^d-

Question 7

What are the products called when the nucleophile was a cyanide ion?

Answer 7

Hydroxynitriles.

Question 8

What can aldehydes be oxidised into and what is the oxidising agent?

Answer 8

Carboxylic acids, acidified potassium dichromate

Question 9

What can aldehydes be reduced into and what is the reducing agent?

Answer 9

Primary alcohols, Sodium tetrehydridoborate(III) NaBH4

Question 10

What can ketones be reduced to?

Answer 10

Secondary alcohols.

Question 11

What happens when an aldehyde is warmed with Tollen’s reagent?

Answer 11

Ag+ is reduced to Ag

Question 12

What happens when an aldehyde is is warmed with Fehling’s solution?

Answer 12

The Cu2+ ions are reduced to Cu+

Question 13

What is the general formula of a carboxylic acid?

Answer 13

R-COOH

Question 14

What is the general formula of an ester?

Answer 14

R-COO-R

Question 15

How do you name an ester?

Answer 15

The name of the second R group is placed first and then the first R group with -oate on the end.

Question 16

Why is the carbonyl group in carboxylic acids more polar than the carbonyl group in aldehydes and ketones?

Answer 16

Due to the second oxygen atom bonded to it.

Question 17

What is the name for the ion produced if the H^d+ is lost from a carboxylic acid and what happens to the charge?

Answer 17

A carboxylate ion, the negative charge is spread over three atoms.

Question 18

Why is a carboxylate ion stable?

Answer 18

Due to the delocalised electrons

Question 19

What is produced when ethanoic acid reacts with sodium hydrogencarbonate?

Answer 19

Sodium ethanoate, CO2 and H2O

Question 20

How are esters produced and what is the name of the reaction?

Answer 20

Carboxylic acids reacting with alcohols with a strong acid catalyst (H2SO4).

Question 21

What is acid hydrolysis of an ester?

Answer 21

Ester + H2O –> Carboxylic acid + alcohol

Question 22

What happens when a base is used to catalyse the hydrolysis of an ester instead of an acid?

Answer 22

the salt of the acid is formed so equlibrium is not reached and more product is formed.

Question 23

Name 4 common uses of esters?

Answer 23

• Solvents,
• Plasticisers,
• Perfumes,
• Food flavourings.

Question 24

What is produced when a triglyceride is reacted with NaOH?

Answer 24

Glycerol and a mixture of sodium salts of the acids that form part of the ester.

Question 25

How is biodiesel produced?

Answer 25

Triglyceride + KOH

Question 26

What is acylation?

Answer 26

The substitution of the acyl group R-CO-R into another molecule.

Question 27

Name 4 acid derivatives that contain an acyl group.

Answer 27

Ester, acyl chloride, acid anhydride and amine.

Question 28

What is ab addition-elimination reaction?

Answer 28

Nucleophile attacks the C^d+ atom, followed by the loss of Z- (the leaving group. R-CO-Z

Question 29

What is the speed of an addition-elimination reaction governed by? 3 things.

Answer 29

- the size of the charge on the carbonyl carbon which depends on the electron attracting power of Z, - How easily Z is lost. - How good the nucleophile is.

Question 30

Name 4 typical nucleophiles.

Answer 30

Primary amine Ammonia Alcohol Water

Question 31

Why would you use propanoyl chloride instead of propanoic acid when preparing methyl-propanoate from methanol?

Answer 31

Its faster as Cl- dissociates more readily.

Question 32

Why would you use propanoic acid rather than propanoyl chloride when preparing methyl-propanoate from methanol?

Answer 32

Propanoyl chloride would produce HCl which is toxic, corrosive and harmful to the environment.