# The hydronium ion $H_3O^+$

## Structure

Click on the image to see the ion from other angles

## Occurence

The hydronium ion is present in the aqueous environment. Its molarity is related to the molarity of the hydroxide ion by the ionic product of water:

$[OH^-][H_3O^+]$ $=$ $10^{-14}\frac{mol}{L}$

In acid medium: $[H_3O^+]\gt10^{-7}\frac{mol}{L}$, so $[OH^-]\lt10^{-7}\frac{mol}{L}$ In neutral medium: $[H_3O^+]=10^{-7}\frac{mol}{L}$, so $[OH^-]=10^{-7}\frac{mol}{L}$ In basic medium: $[H_3O^+]\lt10^{-7}\frac{mol}{L}$, so $[OH^-]\gt10^{-7}\frac{mol}{L}$