[FreneticAmnesic]

I was wondering if anyone could tell me how to answer part three of this question.

What is the pH of i) a 0.15 mol dm-3 solution of HNO3  and ii) a 0.25 mol dm-3  solution of KOH. iii) What is the resulting pH if equal volumes of these two solutions are mixed?

The answer to part i) is 0.82 and the answer to part ii.) is 13.4 and I have been told that the answer to part iii.) is 12.7

but i need to know the method to getting the answer so that I can apply it to my coursework. Any help will be greatly appreciated. Many thanks. xxxx

[Albert]

Imagine you mix 1L of HNO3 solution and 1L of KOH one. You'll have a 2L solution:

H+         +   -OH       -> H20   +    -OH(surplus)
0.15mol  +  0.25mol  ->               0.10mol

So, you'll get a solution that is [OH]=0.05M (0.10mol/2L).

Then, remember that pH + pOH = 14

[FreneticAmnesic]

Thank you so much xxxx