# A patient's urine sample gave a pH reading of 8.2. What is the value of [H_3O^+] in this?

Nov 28, 2015

$6.31 \cdot {10}^{- 9} \text{M}$

#### Explanation:

This is a pretty straightforward problem that can be solved by using the equation

$\textcolor{b l u e}{\left[\text{H"_3"O"^(+)] = 10^(-"pH}\right)}$

In your case, the concentration of hydronium ions, ${\text{H"_3"O}}^{+}$, will be equal to

["H"_3"O"^(+)] = 10^(-8.2) = 6.31 * 10^(-9)"M"

Interestingly enough, the normal pH range for urine lies between $4.8$ and $8.0$, so your patient's urine sample could be an indicator of a metabolic problem.

By comparison, the normal pH range for blood is much less susceptible to variation. For a healthy individual, blood pH ranges from $7.35$ to $7.45$.

This pH range is controlled by the carbonic acid/bicarbonate buffer, one of the body's main buffer systems.