Question

Calculate the hydroxide ion concentration [oh-] for human urine (ph = 6.2). notice this is about hydroxide.

Answer 1

[OH⁻] = 1.6 × 10⁻⁸ mol / dm³

Step-by-step explanation

By definition,
`[\text{H}^(+)] = 10^{-\text{pH}}`, where
`[\text{H}^(+)]` is the concentration of proton in the solution.

pH = 6.2 for this solution. As a result,
`[\text{H}^(+) = 10^(-6.2) = 6.31 * 10^(-7) \; \text{mol} \cdot \text{dm}^(-3)`.

`[\text{H}^(+)] \cdot [\text{OH}^(-)] = \text{K}_w`, where
`[\text{OH}^(-)]` the concentration of hydroxide ions and
`\text{K}_w` is the dissociation constant of water.

`\text{K}_w = 10^(-14) \; \text{mol}\cdot \text{dm}^(-3)` at 0.10 MPa and 25 °C. As a result,
`[\text{OH}^(-)] = \text{K}_w / [\text{H}^(+)] = 10^(14) / (6.31 * 10^(-7)) = 1.6 * 10^(-8) \; \text{mol}\cdot \text{dm}^(-3)`.