Chapter 26

Question 1

Draw the mechanism for the reaction of carbonyl compounds with NaBH4 and name the mechanism

Answer 1

Correct mechanism, name is nucleophilic addition

Question 2

Draw the mechanism for the reaction of carbonyl compounds with NaCN and name the mechanism

Answer 2

Correct mechanism, name is nucelophilic addition

Question 3

Draw the reaction of propanal with HCN, state how the HCN is produced in the reaction (what two reactants)

Answer 3

Correct reaction, NaCN and H2SO4

Question 4

Describe the steps in the mechanism of the reaction with NaBH4

Answer 4

1) lone pair from hydride (H-) attracted and donated to slightly + C atom in the C=O bond
2) A DATIVE covalent bond forms between the Hydride ion and the C
3) pi-bond in C=O breaks by HETEROLYTIC fission, forming a negatively charged intermediate
4) O atom of intermediate donates a lone pair to H in water. The intermediate has been PROTONTED to form an alcohol

Question 5

Describe the steps in the mechanism of the reaction with NaCN/H+

Answer 5

1) lone pair from cyanide (CN-) attracted and donated to slightly + C atom in the C=O bond. A dative covalent bond forms.
2) pi-bond in C=O breaks by HETEROLYTIC fission, forming a negatively charged intermediate
3) O atom of intermediate donates a lone pair to H in water/ H+ ion. The intermediate has been PROTONTED to form the product
4) The product is a Hydroxynitrile.

Question 6

What’s the product called with a CN in?

Answer 6

Hydroxynitrile

Question 7

When drawing hydrogen bonding of carboxylate acids where is the bond drawn?

Answer 7

From the =O to a H of the water.

Question 8

Reaction of Carboxylic Acid with Metals

Answer 8

Salt + H2

Question 9

Reaction of Carboxylic Acid with Bases

Answer 9

Salt + H2O

Question 10

Reaction of Carboxylic Acid with carbonates

Answer 10

Salt + H2O + CO2

Question 11

Name the salt: (HCOO)2Ca

Answer 11

Calcium methanoate (can draw charges of - and 2+ on)

Question 12

Draw the reaction of the esterification of carboxylic acids with alcohol. State the catalyst

Answer 12

Carboxylic Acid + Alcohol —-> Ester + Water

Catalyst is concentrated H2SO4. HEAT

Question 13

Draw the reaction of the esterification of Acid anhydrides with alchols

Answer 13

Acid anhydrides + Alcohol —-> Ester + Carboxylic Acid

Question 14

Draw the reaction of the Acid hydrolysis of esters

Answer 14

Ester + H20 —-> Carboxylic Acid + Alcohol

Reflux with hot aqueous Acid (HCl)

Question 15

Draw the reaction of the alkali hydrolysis of esters

Answer 15

Ester + NaOH- —-> Salt + Alcohol

Reflux with NaOH

Question 16

How do you make Acyl chlorides using SOCl2?

Answer 16

Carboxylic Acid + SOCl2 —-> Acyl chloride + SO2 + HCl

Question 17

What is the name of SOCl2

Answer 17

Thionyl Chloride

Question 18

Acyl chlorides to make Carboxylic Acid

Answer 18

Acyl chloride + H2O —-> Carboxylic Acid + HCl

Question 19

Acyl Chlorides to make an ester?

Answer 19

Acyl Chloride + Alcohol —-> Ester + HCl

Question 20

Acyl Chloride to make a primary aside

Answer 20

Acyl Chloride + NH3 —-> primary amide + HCl

Question 21

Acyl Chlorides to make secondary amides

Answer 21

Acyl Chloride + CH3CH2NH2 —-> secondary amide + HCl

Question 22

Draw out propanamide

Answer 22

Check A3 sheet

Question 23

Draw N-methyl ethanamide

Answer 23

Check A3 sheet

Question 24

What is Tollens reagent used for?

Answer 24

Detecting the presence of an aldehyde group

Question 25

How does tollens reagent distinguish between aldehydes and ketones?

Answer 25

The Aldehyde is OXIDISED to a Carboxylic Acid

The Silver ions are REDUCED to silver Ag+(aq) + e- —-> Ag(s)

Question 26

What is 2,4-DNP used for?

Answer 26

Detecting the presence of a carbonyl group in an organic compound

Question 27

How is the orange precipitate formed when reacting with 2,4-DNP used to distinguish between an aldehyde and ketone?

Answer 27

1) Crystals must be purified - filter wash purify filter wash
2) find melting points of crystals
3) Compare to a database of melting points to find original compound