8O-Aldehydes And Ketones

Question 1

How can aldehydes form a 1° alcohol

Answer 1

Aldehyde can be reduced

Question 2

What is a ketone reduced to

Answer 2

2° alcohol

Question 3

Conditions for nucleophilic addition of aldehydes and ketones with NaBH4

Answer 3

Reducing agent/nucleophile (H- ions attracted to positive carbon in C=O bond) NaBH4 (aq)
Room temp

Question 4

Conditions for catalytic hydrogenation of aldehydes and ketones with H2

Answer 4

H2 and Nickel catalyst
150°c
High pressure

Question 5

What’s the difference between NaBH4 and H2 as reducing agents

Answer 5

NaBH4, only reduces C=O
H2, reduces C=O -CN -NO2 C=C

Question 6

Reaction of ethanal to ethanol

Answer 6

CHO(CH3) +2[H] —> CH3CH2OH

Question 7

Nucleophillic addition of aldehydes—> 1° alcohols and ketones—> 2° alcohols

Give conditions

Answer 7

first arrow: middle of a lone pair on the H- nuclophile to the Delta positive carbon with the oxygen attached

Second arrow: from the middle of the double carbon oxygen bond onto the oxygen

Third arrow: oxygen has a lone pair and a negative charge. Arrow from the Middle of the lone pair onto the H+ catalyst.

NaBH4 (aq)
Room temp

Question 8

Why is the carbonyl group attacked by nucleophiles

Answer 8

Difference in electronegativity between the carbon and oxygen, polar bond, oxygen is more electronegative, carbon atom is s+ and attracts nucleophile

Question 9

What does nucleophilic addition with KCN/HCN produce

Answer 9

hydroxynitrile

Question 10

Nucleophilic addition of aldehydes/ketones to hydroxynitriles with HCN/KCN

Give conditions

Answer 10

first arrow: middle of the lone pair on the cyanide nucleophile To the Delta positive carbon with the oxygen attached

Second arrow: from the middle of the carbon oxygen bond onto the oxygen

Third arrow: leaves the oxygen with a lone pair and a negative charge. The arrow goes from the middle of the lone pair to the hydrogen/H+ catalyst

HCN/KCN
Dilute H2SO4
Room temp

Question 11

How to name a hydroxynitrile

Answer 11

CN need to be on carbon 1

Carbon number-Hydroxy-alkane name (longest chain)-nitrile

Question 12

Why do nucleophillic addition reactions with KCN/HCN produce enantiomers

Answer 12

For aldehydes and unsymmetrical ketones the carbonyl is a trigonal planar, C=O can be approached from both sides by nucleophile forming a racemic mixture

Question 13

What are hazards of using KCN

Answer 13

Toxic gas

Question 14

How to name HC=O attached to a benzene

Answer 14

Benzenecarbaldehyde