# How should the autoprotolysis reaction of water evolve at HIGHER temperature than 298*K?

Apr 30, 2016

Consider the definition of $p H$; it is clearly a BOND BREAKING PHENOMENON

#### Explanation:

By definition, $p H = - {\log}_{10} \left[{H}_{3} {O}^{+}\right]$ $=$ $7$, at $298 \cdot K$.

But this relates to the autoprotolysis reaction:

$2 {H}_{2} O r i g h t \le f t h a r p \infty n s {H}_{3} {O}^{+} + H {O}^{-}$

Since this is a bond-breaking reaction, we would expect that autoprotolysis would become more facile at HIGHER temperature. (Why?). Thus the equilibrium should shift to the right.

Should the equilibrium shift rightwards, ${H}_{3} {O}^{+}$ should reasonably increase. Given the stated definition of $p H$, the value should thus decrease.

But as chemists, as physical scientists, we should seek out the data that inform our argument. From the interwebz, I found that at $333 \cdot K$, $p H = 6.54$. That is $p H$ has decreased corresponding to an increase in ${H}_{3} {O}^{+}$. Therefore it seems that this analysis is not too offbase. If ${H}_{3} {O}^{+}$ has increased, how does $H {O}^{-}$ evolve?