Imhotep's Lab Interactive FAQ

Looking at the PH in document http://www.chem.unep.ch/irptc/sids/oecdsids/Silicates.pdf
I learned something I must had known from high school but had forgotten.

A substance can, it seems, be both a base (Alkaline) and an acid depending upon, I'm guessing,
maybe temperature? Help me out here if someone knows.
The pdf link above comes from How to convert a Lead Acid Battery into an Alkaline Batteryhttp://blog.hasslberger.com/2007/01/how_to_convert_a_lead_acid_bat.html

The web page states "Alum" from the super market spice section and
then incorrectly states Alum is CAS 1344-00-9, sodium aluminum silicate.
The CAS 1344-00-9 is insoluble in water. Do not go buy sodium aluminum silicate.
The pdf link above states Water Solubility to be max 79 mg / liter so that's around
316 mg per gallon. For example: a 2.75 oz of Kroger Alum contains 78g or
78,000 mg of Alum . 316 mg is less than 0.5% of the volume of the Kroger Alum bottle.