O Levels Chemistry (5070)•5070/11/M/J/23
Explanation
Constructing the displayed formula of the ester propyl methanoate
Steps:
- Parse the name: "propyl methanoate" indicates an ester from methanoic acid (HCOOH) and propan-1-ol (CH3CH2CH2OH).
- Form the ester linkage: replace -OH from the acid and -H from the alcohol to get H-C(=O)-O-CH2CH2CH3.
- Expand to displayed formula: show all atoms and bonds explicitly as H connected to C double-bonded to O, single-bonded to O-CH2-CH2-CH3.
- Select the option matching this structure.
Why D is correct:
- D shows the exact arrangement H-C(=O)-O-CH2-CH2-CH3, matching the IUPAC formula for the ester from formic acid and propanol.
Why the others are wrong:
- A: Depicts ethyl methanoate with a shorter alkyl chain (two carbons instead of three).
- B: Shows methyl propanoate, reversing the acid and alcohol parts.
- C: Represents propanoic acid, lacking the ester oxygen linkage.
Final answer: D
Topic: Formulae, functional groups and terminology
Practice more O Levels Chemistry (5070) questions on mMCQ.me