a buffer is prepared by mixing .208 L of 0.452 M HCl and 0.5 L of 0.4 M sodium acetate. When the Ka= 1.8 x 10^-5

I figured out that the pH= 4.74

but then it asks how many grams of KOH must be added to the buffer to change the pH by .155 units?

3 answers

Show me how you obtained pH = 4.74. I can't get that. My answer looked more like 4.79.
Since Ka a measure of H+ ions,
-log(Ka)= pH.. my assignment says that part is right, I just don't know what to do from there to get M -> moles -> grams
-log Ka = pKa which may or may not be = pH. Ka is a measure of how strong/weak the acid is.