# Problem: A certain indicator HIn has a pKa of 3.00 and a color change becomes visible when 7.00% of the indicator has been converted to In-. At what pH is this color change visible?

###### FREE Expert Solution

To solve for pH, we use the Henderson-Hasselbalch equation:

We are given the following:

pKa = 3.00
In- = 7.00%
HIn = 93.00%

Since in the equation, we just need to compare the ratio of conjugate and weak acid present, we can directly plug-in the given percentages to the equation, thus we solve for pH:

###### Problem Details

A certain indicator HIn has a pKa of 3.00 and a color change becomes visible when 7.00% of the indicator has been converted to In-. At what pH is this color change visible?