Year 13- Aldehydes and ketones

Question 1

What are carbonyls?

Answer 1

compounds with a C=O bond

Question 2

Oxidation of aldehydes- product, reagents and conditions

Answer 2

carboxylic acids
potassium dichromate solution and dilute sulfuric acids
heat under reflux

Question 3

How is tollens reagent formed?

Answer 3

mixing aqueous ammonia and silver nitrate

Question 4

Reduction of carbonyls-reagents

Answer 4

NaBH4 in aqueous ethanol or LiAlH4

Question 5

What is another way carbonyls are reduced?- reagents and conditions

Answer 5

Catalytic hydrogenation
hydrogen and nickel catalyst
high temp and pressure

Question 6

Carbonyls + hydrogen cyanide- product, reageny, conditions and mechanism

Answer 6

hydroxynitriles
sodiumcyanide and dilute sulfuric acid
room temp and pressure
nucleophilic addition

Question 7

What is a disadvantage of HCN?

Answer 7

it is a toxic gas that is difficult to contain

Question 8

What is an advantage of using KCN or NaCN?

Answer 8

produces a higher conc of CN- ions

Question 9

Why does the nucleophilic addition reaction of KCN can produce a mixture of enantiomers?

Answer 9

Aldehydes and ketones are unsymmertrical and the trigonal planar carbonyl can be attacked by the KCN from both sides