Re: Why is hydrogen carbonate(or hydrogen sulfate) called 'Bi' carbonate, 'Bi

"Bi" is derived from the Latin "bis", meaning "twice".  The bi in 
bicarbonate, refers to the fact that it takes twice as many equivalents 
(or moles) of bicarbonate ions to neutralize an acid compared to carbonate 
ions.  The same reasoning applies to bisulfate, bisulfite, etc.  These 
anions were also referred to with "acid" nomenclature.  For example, 
sodium acid sulfate.

The preferred nomenclature now is "hydrogen", as in sodium hydrogen 
sulfate.



Webster's New Universal Unabridged Dictionary, Simon & Schuster, 1979