Battery acid is sulfuric acid. Sulfuric acid is very corrosive and will burn your skin if not washed off very quickly.
BOOM
You will ruin the battery.
if you touch it not much but if you drink it will kill you
it will burn through your skin
Water or acid.
You will die.
YES, battery acid isn't something that should touch your skin, ever.
The battery would lose its acid.
it will cause a chemical reaction between the two materials
The acid turns to water. Batteries will freeze in cold weather if they are discharged. When the battery is charged, the water turns back to acid.
A battery acid is a variety of acid used as an electrolyte in a battery - usually sulphuric acid.
I assume we're talking about the typical wet-cell battery. Usually it is filled with a mixture of acid and water. If the water is gone the battery is damaged and cannot be fixed by refilling it with acid and water.