The answer is 4.47 x 10^{-4} M.

Solution:

- [H+] = 10
^{(-pH)} - [H+] = 10
^{(-3.35)} - [H+] = 4.47 x 10
^{-4M}

pH is a logarithmic measure of the hydrogen ion concentration of an aqueous solution:

- pH = -log[H+]

log is the base 10 logarithm and [H+] is the hydrogen ion concentration in moles per liter

The word "pH" was first described in 1909 by Danish biochemist Søren Peter Lauritz Sørensen. pH is an acronym for "power of hydrogen" where "p" is short for the German word for power, potenz and H is the element symbol for hydrogen.

Tip! Here's a quick review of how to calculate pH and what pH means with respect to hydrogen ion concentration, acids, and bases at *Chemistry.about.com*.