- #1
RoboNerd
- 410
- 11
Homework Statement
I found this problem online for extra practice for my AP Chem class.
https://www.quia.com/files/quia/users/jpugteach/APChem/AP-Chem-Chapter-19-Graphs.pdf
The problem in question is number 4.
I do not understand how to solve it and why the answer D is correct.
Homework Equations
Henderson Hasselbalch Equation
The Attempt at a Solution
Assuming I have an indicator of the form HIn <------> H+ + In-I know that my indicator will have a visible change when the ratio of In- to HIn will be 1/10.
So I have pH = pKa + log ( [A-] / [HA] ) = -log ( 1.8 * 10 E -5 ) + log (1/10) = 3.744.
So I put down that my answer was B as my calculated pH falls in that range.
What am I doing wrong here?
Thanks in advance for the help![/B]