Answer
Acid
Procedure
pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.
As with the hydrogen-ion concentration, the concentration of the hydroxide ion can be expressed logarithmically by the pOH.
We have that pH + pOH = 14
Therefore pH= 14- pOH
In this case, we have pH= 14-9 = 5
A pH of 5 is similar to that of coffee, therefore the best answer is: acid