pH adjustment - (May/02/2010 )

Hello everybody,

I wonder if there is a formula to calculate the volume of a concentrated acid (say Nitric acid 70% w/w) to 1 lit of distilled water to make a final pH of, say 5 ? I need to use the formula with different density of HNO3 (e.g. 95%) and also it may be added to 1 lit of water with pH=6 instead of a distilled water. How to calculate what would be the final pH of our solution?

You can't control pH of a solution this way. Read about pH buffers, starting perhaps here:
http://en.wikipedia.org/wiki/Buffer_solution