multiple choice question-PH? (1 Viewer)

[renny 123]

A sulfuric acid solution has a concentration of 5 x 10^-4 mol L^-1
What is the pH of this solution, assuming the acid is completely ionised?

a) 3.0
b) 3.3
c) 3.6
d) 4.0

Using the calculator and -log(5 x 10^-4) the answer is 3.3 however the answer is actually a)
not sure why, is it something to do with a decimal place rule?
Thanks

 

[kaz1]

Sulfuric acid is diprotic hence you have to double the actual concentration to get the hydrogen ion concentration. So the hydrogen ion concentration is 10^-3.

 

[renny 123]

ohhh yer. I thought I must have been missing something. I forgot about that
Thanks heaps