# How are buffers made?

Jul 14, 2017

Take a weak acid, and add approx. 1/2 equiv of strong base........

#### Explanation:

Alternatively, take a weak base, and add approx. 1/2 equiv of strong acid......

Anyway, take a look at this old answer which derives the buffer equation.........

${\underbrace{- {\log}_{10} \left[{H}_{3} {O}^{+}\right]}}_{\text{pH}} = {\underbrace{- {\log}_{10} {K}_{a}}}_{p {K}_{a}} + {\log}_{10} \left\{\frac{\left[{A}^{-}\right]}{\left[H A\right]}\right\}$

i.e. $\text{pH} = p {K}_{a} + {\log}_{10} \left\{\frac{\left[{A}^{-}\right]}{\left[H A\right]}\right\}$

And thus we need an acid whose $p {K}_{a}$ is TOLERABLY close to the value of the $p H$ whose value you are trying to regulate. Is this clear?