Question

Please help I don’t understand

Answer 1

`C. \ \ \ \ 7`

Step-by-step explanation:

The pH value is a unit of measure which describes the degree of acidity or alkalinity of an aqueous solution. In other words, pH demonstrates the quantitative information of the activity of an acid or base based on hydrogen ion concentration.

The mathematically formal definition of pH is the negative logarithm of hydrogen ion concentration:

`pH \ \ = \ \ -\log_(10)\left[H^(+)\right]`.

Hence, if the concentration of
`\text{H}^(+)` ions in a solution is
`1.0 \ * \ {10}^(-7) \ \text{M}`,

`pH \ = \ -\log_(10)\displaystyle{\left(1 \ * \ {10}^(-7)\right)} \\ \\ pH \ = \ -\log_(10)\displaystyle{\left(1\right) \ - \ \log_(10)\left({10}^(-7)\right)} \\ \\ pH \ = \ 0 \ - \ \left(-7\right) \\ \\ pH \ = \ 7`.