Question

What method is used to distinguish between different molecular compounds that contain the same elements?

Answer 1

It is hard to address this question definitively.....

Explanation:

Let's assume you have the chemical formula `C_5H_12`.....Three structural isomers can be generated by this formula: (i) `"n-pentane", H_3C-CH_2CH_2CH_2CH_3;` (ii) `"isobutane", H_3C-CH(CH_3)CH_3;` and (iii) `"neopentane", C(CH_3)_4`.

And we have to choose a spectroscopic means to differentiate these isomers. In this scenario the best means is `""^1H` `"NMR spectroscopy"`, which for isomers, (i), (ii), and (iii), would generate 3 signals, 2 signals, and 1 signal respectively......the first two with the appropriate integral ratio, i.e. `6:4:2`, and `9:1`.