carbonyl chemistry

Question 1

what is an aldehyde?

Answer 1

formed from partial oxidation of primary alcohols
-CHO group at end of chain

Question 2

what is a ketone group?

Answer 2

formed from oxidation of secondary alcohols
-CO group in centre of chain

Question 3

naming carbonyls

Answer 3

aldehyde suffix -al
ketone suffix -one

Question 4

reduction of carbonyls

Answer 4

reagents - NaBH4
conditions - in aqueous solution, warm
mechanism - nucleophilic addition

Question 5

reduction of aldehydes

Answer 5

reduced to primary alcohol
RCHO + 2[H] -> RCH2OH

Question 6

reduction of ketones

Answer 6

reduced to secondary alcohols
R1COR2 + 2[H] -> R1CHOHR2

Question 7

reaction of carbonyls with HCN

Answer 7

reagents = HCN or NaCN/H+
increases chain length
nucleophilic addition
forms a hydroxynitrile

Question 8

test for an aldehyde

Answer 8

add tollen’s reagent
heat at 60oC for 5-10 minutes
silver mirror forms

Question 9

test for a carbonyl

Answer 9

add 2,4-DNPH
yellow/orange precipitate forms

Question 10

identifying a carbonyl compound

Answer 10

purify yellow/orange precipitate
find the melting point
compare with known data