Question

How many isomeric esters including structural isomers and stereoisomers can be made with the molecular formula C5H10O2 if methanoic acid is one if the two reactants used.

A: 2. B: 3 C: 4 D: 5

Answer 1

Methanoic acid has a molecular formula of HCOOH, when form an ester it's HCOO-, so the rest of the ester is -C4H9, a saturated 4 carbon chain.  As shown in the attached diagram, there are 4 structural isomers, and the third isomer has 2 stereoisomers. So the answers is D:5.