a) Calculate the change in pH when 4.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq).

b) Calculate the change in pH when 4.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

4 answers

I've worked this, or at least a variation of it, earlier today. If you can't find it let me know and I'll try to find it and give you a link.
I tried doing it and got for a) -0.03 and b) 0.03 but the program keeps telling me I have the wrong answers... I don't know what I am doing wrong.
If you had posted your work I could have found your error by now. You didn't and I have no idea what you've done. Here is a link to the other one.
http://www.jiskha.com/display.cgi?id=1332885681
(a) 60 mL of 0.100 M HCl and 10.0 mL of 0.480 M HCl