The acid used is generally Sulphuric Acid. You cannot change it to another type of acid such as "Citric" Yes you can change it, but why do you want to? I WOULD NOT recommended it for anyone not trained how to do it.
In any case if the acid is depleted the battery will most likely be useless too.
Perhaps you should check the specific gravity and add DISTILLED water as necessary, about 5mm above the plates should be OK.
Chemical.
Car battery acid consists of Hydrochloric acid and Sulphuric acid.
Car or automotive battery acid is 30-50% sulfuric acid
A car battery has sulfuric (sulphuric) acid in it.
It's an acid.
acid
The pH of car battery acid is normally around 1 (extremely acidic).
Lead - acid
It is sulphuric acid.
It's an acid.
Sulfuric Acid
Sulphuric acid