# Question #bc883

Apr 15, 2017

Hydroxide, $O {H}^{-} 1$

#### Explanation:

Hydroxide makes solutions basic, hydrogen ions (${H}^{\text{+1}}$) makes solutions acidic.

One water molecule is made up of one hydroxide molecule and one hydrogen ion. So when water dissociates, there is one of each. This is why in water the concentrations are equal and so water is neutral.

[Hydroxide] = [Hydrogen] $\implies$ neutral, pH = 7 (water only)
[Hydroxide] < [Hydrogen] $\implies$ acidic, pH > 7
[Hydroxide] > [Hydrogen] $\implies$ basic, pH < 7

Note:
[Hydroxide] * [Hydrogen] = $1 \cdot {10}^{-} 14 M$

So [Hydroxide] and [Hydrogen] are inversely proportional: when one goes up, the other must go down.