What I said up above *points* was that a solution would have to have more than 100,000,000 times the concentration of... Fuck it; I'll say this in easy terms.
Say this shit I'm talking about (hydrogen ions) are red pixels.
Water is a white circle with some red pixels in it.
Something with a pH less than 7 has MORE red pixels than that water circle has.
Now, to have a -1 pH, you'd have to have 100,000,000 time more pixels than that white circle. If the circle is... say... .00001% red pixels (
BECAUSE THAT IS THE ACTUAL PERCENTAGE OF HYDROGEN IONS IN PURE WATER), then your substance with a negative pH would have to be 1000% red pixels which is a physical impossibility.
This circle:

cannot have more red pixels in it than it already does. It's 100% red pixels. It's already composed of ALL red pixels.