# How do acids and bases differ?

Jun 16, 2018

Given a specific solvent.....

#### Explanation:

...the ACID is the characteristic cation of the solvent, and any acidic substance added to it will cause an increase in the concentration of this cation. And a base is the characteristic anion of the solvent, and any basic substance added to it will cause an increase in the concentration of this anion.

Water is a solvent for which this equilibrium is well-quantified, and under standard conditions....

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

Where ${K}_{\text{autoprotolysis}} = \left[{H}_{3} {O}^{+}\right] \left[H {O}^{-}\right] = {10}^{-} 14$

And of course, we can take ${\log}_{10}$ of both sides of this expression to give....

${\log}_{10} \left\{\left[{H}_{3} {O}^{+}\right] \left[H {O}^{-}\right]\right\} = {\underbrace{{\log}_{10} {10}^{-} 14}}_{\text{= -14 by definition of the log function}}$

And so we get....

${\underbrace{- {\log}_{10} \left[{H}_{3} {O}^{+}\right]}}_{\text{pH"underbrace(-log_10[HO^-])_"pOH}} = 14$

And at last an expression you will use habitually...

$p H + p O H = 14$

And so given an aqueous solution that is highly acidic, $p O H$ tends high....$p H$ tends low to negative...and in a base solution vice versa. Got all that?