Acids & Bases Problem Set

Acids & Bases Problem Set

Question 3: Physiological pH

Tutorial to help answer the question

Physiological pH is 7.4. What is the hydrogen ion concentration of a solution at physiological pH?

A. -7.4 M

B. 0.6 M

C. 0.6 x 10^{- 8} M

D. 1 x 10^{- 8} M

E. 4 x 10^{- 8}

Tutorial

Calculating H⁺ concentration from pH

pH is the negative log of the hydrogen concentration, i.e.

if pH = -log [H⁺],

then [H⁺] = antilog (-pH) = 10^{- 7.4} M

Thus, the hydrogen ion concentration of a solution at physiological pH (7.4) is
10^{- 7.4}, which is equal to 3.98 x 10^{- 8} M. We can round off to 4 x 10^{- 8} M.

The Biology Project
Department of Biochemistry and Molecular Biophysics
The University of Arizona
January 6, 1999
Revised: October 2004
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