What does pOH mean?

Question

What does pOH mean?

1 Answer

Impact of this question

2181 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-05-26T18:56:56

$pOH$ $=$ $-log_10[HO^-]$

Explanation:

So $pOH$ is the basic counterpart of $pH$ $(=-log_10[H_3O^+])$ .

This derives from the autoprotolysis reaction in water:

$2H_2O(l) rightleftharpoons H_3O^+ + HO^-$

This equilibrium has been carefully measured, and at $298K$ we write,

$K_w=[HO^-][H_3O^+]$ $=$ $10^-14$ .

We can take $log_10$ of both sides to give:

$log_10K_w$ $=$ $log_10[HO^-] + log_10[H_3O^+]$ $=$ $log_10{10^-14}$

$log_10K_w$ $=$ $log_10[HO^-] + log_10[H_3O^+]$ $=$ $-14$ (because by definition, $log_a(a^b)=b$ . On rearrangement:

$14=-log_10[HO^-] - log_10[H_3O^+]$

And, again by definition,

$pH + pOH =14$

The autoprotolysis of water is a bond breaking reaction. How would you predict $K_w$ to evolve at elevated temperature? What would this mean with respect to $pH$ and $pOH$ ?

Science

Math

Humanities

... and beyond

What does pOH mean?

1 Answer

Explanation:

Related questions

Impact of this question