# Question #cc892

May 1, 2016

The question you pose bears no relation to the one in the graphic for which the answer is D.

#### Explanation:

pH is defined as;

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

This means that in coffee $\left[{H}^{+}\right] = {10}^{- 5} \text{ ""mol/l}$

and in tap water $\left[{H}^{+}\right] = {10}^{- 8} \text{ ""mol/l}$

So you can see that the ${H}^{+}$ ion concentration in coffee is greater by a factor of ${10}^{3}$ or 1000 compared to tap water.