# Are all hydroxides basic? What makes a base basic, and an acid acidic?

Feb 4, 2018

Both ${H}_{2} S {O}_{4}$ and $H N {O}_{3}$ contain hydroxides....i.e. ""^(-)O-stackrel+N=O(OH), and ${\left(H O\right)}_{2} S {\left(= O\right)}_{2}$

#### Explanation:

Both ${H}_{2} S {O}_{4}$ and $H N {O}_{3}$ contain hydroxides....and yet these are STRONG acids....

And an acid is typically the hydroxide of a non-metal, whereas a base is typically the hydroxide of a metal.

Non-metals, from the right hand side of the Periodic Table as we face it, TEND to polarize the electron density towards themselves, thereby weakening the $O - H$ bond of their HYDROXIDES. On the other hand, metals, tend to have their electron density REMOVED by the oxygen centre....

Here we got $B {\left(O H\right)}_{3}$...and the oxygen TENDS to polarize the electron density of the $O - H$ bond TOWARDS itself...

${\left(\stackrel{\delta +}{H} - \stackrel{\delta -}{O} -\right)}_{3} B$

....and this the $H - O$ is WEAKENED somewhat....$p {K}_{a} = 9.24$