SolutionsRecent Milestones
1. Two lactic acids
Why does the tetrahedral carbon of van 't Hoff and Le Bel explain the existence of two lactic acids with the same properties, except for their effect on polarized light?
If a tetrahedral carbon has four different substituents (in lactic acid: H, CH3, OH and COOH), two molecules can be built that are non-superimposable mirror images. They have the same physical and chemical properties, but they rotate polarized light in opposite directions.
2. Match them
Match each researcher with his contribution:
- Pasteur
- Pauling
- Barton
- Purcell and Bloch
Conformational analysis · nuclear magnetic resonance · nature of the chemical bond · separation of tartrate crystals
- Pasteur: separation of the two kinds of tartrate crystals.
- Pauling: nature of the chemical bond and resonance theory.
- Barton: conformational analysis.
- Purcell and Bloch: nuclear magnetic resonance.