The concentration of H+ ions in a solution is #1.0 xx 10^-12# M. What is the pH of the solution?

1 Answer
May 30, 2017

Answer:

#12.00#

Explanation:

We're asked to calculate the #"pH"# of a solution with a known hydrogen (hydronium) ion concentration (#["H"^+]# or #["H"_3"O"^+]#; they both represent the same thing in this case).

To calculate the #"pH"# of a solution from a known #["H"^+]#, we can use the formula

#"pH" = -log["H"^+]#

That is, the #"pH"# of a solution is the negative of the logarithm of the hydronium/hydrogen ion concentration.

Using this formula, we have

#"pH" = -log(1.0 xx 10^-12M) = color(red)(12.00#

The number of significant figures in the #["H"^+]# is equal to the number of decimal places of the #"pH"#, so the #"pH"# is #12.00#.