Practical: making and testing the smell of some esters in the lab
3 marks · Easy| Alcohol used | Carboxylic acid used | Ester formed | Smell |
|---|---|---|---|
| Ethanol | Ethanoic acid | Ethyl ethanoate | Fruity, sweet |
| Propan-1-ol | Propanoic acid | Propyl propanoate | Banana-like |
| Butanol | Butanoic acid | Butyl butanoate | Pineapple |
Which combination produces an ester that smells like pineapple?
State the alcohol and carboxylic acid needed to make an ester with a banana-like smell.
Suggest one reason why not much ester is formed during these short laboratory reactions.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Butanol and butanoic acid
(b) Propan-1-ol and propanoic acid
(c) The reaction time is short, so little ester is produced / The reaction is slow at the laboratory scale
Common mistakes: Choosing the wrong row from the table; Not stating both starting chemicals
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies butanol and butanoic acid (or butyl butanoate) as producing the pineapple-smelling ester.
B2 (b) · 1 mark · States propan-1-ol and propanoic acid (or propyl propanoate).
B3 (c) · 1 mark · Gives a reasonable reason for low yield: short reaction time or slow reaction.
Worked solution
(a) Butanol and butanoic acid (row 3) produce the pineapple-smelling ester.
(b) Propan-1-ol and propanoic acid are needed to make the banana-like smelling ester.
(c) Little ester is formed because the reaction is only heated for a short time.