The "fluoride" is often present in the range of 1.4 ppm. But, in reality, this total fluoride is a mixture of F- and HF because HF is a weak acid. Municipal drinking water frequently has fluoride added to improve the dental health of the citizens. Assuming the water is buffered sufficiently to assure that its pH is 5.6 and the concentration is 1.4ppm "fluoride", discuss what percentage of the "fluoride" exists as fluoride ion, F-, and what percentage exists as HF molecules?