M Prep | MCAT 2015 Question of the Day - Prep, Practice Questions, and More!

Q:	Hydrogenation reactions are usually also reduction reactions, whereas protonation is not reduction. The primary reason for this is:

protonation only occurs with nitrogen and oxygen atoms.

hydrogenation does not affect the oxidation state while protonation does.

protons do not come with electrons while hydrogen atoms in hydrogenation do come with electrons.

protons are too small to reduce compounds.