How Many Isomers Exist for C3H6O2?

[Kyoma]

Homework Statement

How many isomers are there in the molecular formula C₃H₆O₂?

Solution:

I know that the above molecular formula is propanoic acid, but it doesn't help. I wasted some time drawing structural formulas and I got 3 as the answer. Is there any short-cut way to find the answer? Thanks.

 

[Borek]

No shortcuts. And there are many, many more than 3.