1. The problem statement, all variables and given/known data What is the total number of isomeric carboxylic acids and esters having the molecular formula C4H8O2? A.6 B.5 C.4 D.3 E.2 2. Relevant equations 3. The attempt at a solution My answer was 4. The isomers I got was: -2-methyl propanoic acid -butanoic acid -methyl propanoate -ethyl ethanoate Did I miss any? Cheers!