Question

10. A basic solution of Al(OH)3, has a pH of 9.85, what is the [OH-] concentration of the aluminum

hydroxide solution? *

Answer 1

Answer:
`[OH^(-)]` of the aluminium hydroxide solution is
`1.41 * 10^(-6)`.

Step-by-step explanation:

It is given that pH is 9.85 and the relation between pH and concentration of ions is as follows.

pH =
`-log [H^(+)]`

9.85 =
`-log [H^(+)]`

antilog (9.85) =
`[H^(+)]`

`[H^(+)] = 7.1 *10^(-9)`

We also know that,

`[H^(+)][OH^(-)] = 10^(-14)`

`[OH^(-)] = (10^(-14))/(7.1 * 10^(-9))`

=
`1.41 * 10^(-6)`

Therefore, we can conclude that
`[OH^(-)]` of the aluminium hydroxide solution is
`1.41 * 10^(-6)`.

Answer 2

Answer: The
`[OH-]` concentration of the aluminum hydroxide solution is
`1.41* 10^(-10)`

Step-by-step explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pOH is calculated by taking negative logarithm of hydroxide ion concentration.

`pOH=-\log [OH^-]`

Putting in the values:

`9.85=-\log[OH^-]`

`[OH^-]=10^(-9.85)=1.41* 10^(-10)`

Thus the
`[OH-]` concentration of the aluminum hydroxide solution is
`1.41* 10^(-10)`