hydrogen carbonate
— Noun
– English
~ a salt of carbonic acid (containing the anion HCO3) in which one hydrogen atom has been replaced; an acid carbonate
hydrogen atom
— Noun
– English
~ an atom of hydrogen
hydrogenation
— Noun
– English
~ a chemical process that adds hydrogen atoms to an unsaturated oil; "food producers use hydrogenation to keep fat from becoming rancid"