[x33lovely]

Are these statements Always True, Sometimes True, or Never True?

1) In an acidic solution, [H+] is greater than [OH-].
2) The pH of a solution that is 1.0M HCl is zero.
3) If the [H+] in a solution increases, the [OH-] must decrease.
4) The [OH-] is less than 10^ -7 M in a basic solution
5) The definition of pH is the negative logarithm of the hydroxide-ion concentration.


I think
1) Always True
2) Sometimes True
3) Always True
4) Never True
And for 5, I'm not sure.

Can someone provide me with some closure? Thanks

[Yggdrasil]

For 2, I agree with your answer although if the statement were worded differently (the pH of a 1.0M HCl solution is greater than zero), always true would be correct.

For 5, you should know this one.  What is the definition of pH?

[Borek]

I am afraid a lot depends on the level this question is asked and on the teacher asking. In high school things like activity are not mentioned, so could be that the answer expected is that 2 and 5 are always true - even if in reality they are not.