Gchem pH values

[jedaerrow]

---

Members do not see this ad.

Can anyone teach me how to solve this problem?

What is the pH of 1.0x10^-4M Ca(OH)2 solution?

How do you do the calculation of logs?

 

[srb711]

Ok... so i'm not sure if I will explain this correctly, but here it goes:

Ca(OH)2 will give off 2 OH ions. So you need to multiply the concentration by 2. So the [OH] is now 2x10^-4.

pOH = -log [OH]

pOH = -log[2x10^-4]

since -log of 1x10^-4 = 4, then -log 2x10^-4 will be a little less than 4, ~ 3.8 or so.

pH = 14 - pOH, so pH = 10.2

They're not likely to give you another answer that is within decimal points of the correct one, so as long as you round reasonably then you should be able to get the right answer.