What 2 organic compounds can be usually found together? What could be infered from this?

Question

What 2 organic compounds can be usually found together? What could be infered from this?

Answer 1

There are probably many pairs, and much of this depends upon what you call an Organic compound.

If you just mean compounds containing Carbon, then the equilibrium of CO2 and H2CO3 is a classic pair:

CO2 + H2O  <==>  H2CO3

Some compounds like N-Acetyl-L-Proline exist in two structural forms called cis- and trans-.  These can isomerize from one to another and are almost always found together (in different proportions).  Maleic acid  and Fumaric acid are another cis-trans pair of compounds which can inter-convert.

The inference of two compounds that are usually found together is that they are chemically related and can either inter-convert directly or one can react with a very common substance to form the other.