Question

You are asked by your research supervisor to prepare 1L of 1M Tris-HCl, pH 6.8. The molecular weight of Tris-HCl is 157.59. Show your calculations in preparation of this buffer. The pH of the Tris-HCl solution will be acidic. In general, how would you change the pH of the solution to 6.8?

Answer 1

you wanna use the Henderson-Hasselbalch equation:

\(\sf pH=pKa+log\dfrac{[A^-]}{[HA]}\)

where HA is the acid and \(A^-\) is the conjugate base.

Find the concentrations of each necessary to make the pH 6.8 by pluggin in pH and pKa, then solving.

Answer 2

First you need to make the 1M solution and then adjust the acidity.