Why do Acids have to have funny names anyways?

So why is HCl hydrochloric acid instead of just plain old hydrogen chloride? Well, it is so that Chemistry teachers can torture their students by making them learn yet another different set of rules for naming stuff.

Well not really, but it might seem like that. And you actually have to know how to do it even if the only reason is a tortuous teacher (tortuous: adjective - not direct or straightforward; one who tortures) so you may as well try to get the rules figured out.

The naming rules are all based on the anion in the chemical formula for the acid. Remember the anion is the negative part so it will always come second. And the anion might be just one element, like in HCl or H2S. Or it might be a polyatomic ion like in HNO3 or H3PO4. The ending of the name of the anion tells you how the acid will be named.

Three rules:

1. anion ends in "ide" the acid will be named hydro_____ic acid

• HCl, anion is chloride, acid name is hydrochloric acid
• H2S, anion of sulfide, acid name if hydrosulfuric acid

2. anion ends in "ite" the acid will be named ______ous acid

• HNO2, anion is nitrite, acid name is nitrous acid
• H2SO3, anion is sulfite, acid name is sulfurous acid

3. anion ends in "ate" the acid will be named _______ic acid

• H2CO3, anion is carbonate, acid name is carbonic acid
• H2SO4, anion is sulfate, acid name is sulfuric acid

But WHY do they have these confusing naming rules that seem to just be made up out of nowhere? It's based on an older system of naming that used name suffixes instead of number to give information about the compound. The compounds that we use Roman Numerals to name used to use -ous and -ic endings instead to show which charge the metal had in that compound. The larger of the 2 possible charges got the -ic ending and the smaller got the -ous ending. So instead of Hg II chloride it would have been mercuric chloride.

Anyways, acids still use this older naming system with the different endings telling you what to put in the formula.