The Kilcher Homestead is a 600 acre Pioneer Homestead that has been protected for perpetuity via a ConservatIon Easement. The Kilcher Family has also preserved the Historic Cabin and site as a LIving Museum.
Yes, negative pH is possible, but not in water as a solvent. The range of pH in water is 0 to 14 (to be more precise, it is -1.7 to 15.7, but for simplicity's sake, we start with the usual values.) Thus, what pH indicates is the ability of the acid to form H3O+, which can then donate a proton.
CO2 gas, when dissolved in blood, is the second largest group of negative ions of blood plasma. Hence, breathing directly affects blood pH. In its turn, blood pH is tightly monitored within a very narrow range (from about 7.3 to 7.5) by the group of nerve cells located in the medulla oblongata in order to have normal-body biochemistry.