# Why does calcium hydroxide raise soil pH?

Jul 8, 2018

Well its a basic compound after all...

#### Explanation:

Calcium hydroxide has a chemical formula of $C a {\left(O H\right)}_{2}$. The two hydroxide ions are responsible for it being a base. Adding it to soil neutralizes the acid, which turns the ${H}^{+}$ into water molecules, therefore decreasing their concentration in the process. This therefore increases the $\text{pH}$ of the soil, as $\text{pH}$ is defined by the equation:

$\text{pH} = - \log \left[{H}^{+}\right]$

where:

• $\left[{H}^{+}\right]$ is the hydrogen ion concentration in terms of molarity

$\text{pH}$ is inversely proportional to the ${H}^{+}$ ion concentration. Higher ${H}^{+}$ concentration means lower $\text{pH}$ and vice-versa.