Aldehydes and Ketones

Question 1

Aldehyde

Answer 1

R-H-C=O
-al

Question 2

Ketone

Answer 2

R-R-C=O
-one

Question 3

Oxidation of Aldehydes

Answer 3

Can be oxidised into Carboxylic Acids

Question 4

Oxidation of Ketones

Answer 4

Cannot be oxidised

Question 5

Oxidising agent for Aldehydes

Answer 5

Acidified K2Cr2O7
Orange to Green

Question 6

Tollens Reagent

Answer 6

Colourless solutiuon of silver nitrate dissolved in aqueous ammonia
Silver mirror formed when heated with an aldehyde

Question 7

Fehling’s solution

Answer 7

Blue soloution of Cu2+ ions dissolved in NaOH
Brick red ppt formed when warmed with an aldehyde

Question 8

Reduction of Aldehydes

Answer 8

Can be reduced back to primary alcohol using NaBH4 in aqueous methanol, (generates H- nucleophile)

Question 9

Reduction of Ketones

Answer 9

Can be reduced back to secondary alcohols using NaBH4 dissolved in aqueous methanol, (generates H- nucleophile)

Question 10

Reducing Agent for reduction of Aldehydes/Ketones

Answer 10

NaBH4 dissolved in aqueous methanol

Question 11

By what mechanism will Potassium Cyanide react with carbonyls?

Answer 11

Nucleophilic Addition

Question 12

What do Aldehydes or Unsymmetrical Ketones form when they react with KCN followed by dilute acid?

Answer 12

Enantiomers, as the CN- may attack from above or below

Question 13

Hazards of using KCN

Answer 13

Irritant, highly toxic gas, reacts with moisture to form HCN