Question

What is the hydrogen ion and hydroxide ion concentration for a pOH of 6.840? Is the solution an acid or a base

Answer 1

To solve the problem you need to use the following formulas to determine the pH and the pOH.

1) pH=−log[H3O+]

2) pOH=−log[OH−]

3) 14.00=pH+pOH

Given that the pOH is 6.840 the pH will be

pH=14.00-6.840=7.160

To determine the concentrations we need to solve equations 1) and 2). This gives us

`[H_3O^+]=10^(-pH)`
`[OH^-]=10^(-pOH)`

Solving using the pH and pOH values

`[H_3O^+]=10^(-7.16)=6.9183*10^(-8)\text{ M}`
`[OH^-]=10^(-6.84)=1.4454\text{ }*10^(-7)\text{ M}`