MyPinkBunny Posted October 3, 2011 Posted October 3, 2011 Help on Biochemistry (Buffers and pH) The buffer is 4 mL of 0.1M Tris, pH 9 undiluted. We will add 1 mL of 0.05 N HCL. What is the expected pH. I took the henderson-hasselbach equation pH = pka + log [base]/[acid] and plugged in pka = 8.21 and [base]=0.1 M and [acid]=.05 M and got a pH of 8.51 but apparently that was wrong. The answer is 8.65. I have no idea how to arrive at 8.65. I'm guessing you have to take into account the 4 mL and the 0.05 N HCL, but I don't know how to do that. Please can anyone help guide me in the right direction? I've been working on this problem for hours and our class doesn't have a textbook with examples. Thank you!
CharonY Posted October 3, 2011 Posted October 3, 2011 What you have to take into account is the final concentration in your solution. So you have to take the dilution into account as a result of mixing. Hint1: the final volume is 5 ml.
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