The formula for determining the pH of a solution is pH = -log[H+], where [H+] is the hydrogen ion concentration (in M/L). What is the hydrogen ion concentration of an acid with a pH of 2.5?

Question

The formula for determining the pH of a solution is pH = -log[H+], where [H+] is the hydrogen ion concentration (in M/L).  What is the hydrogen ion concentration of an acid with a pH of 2.5?

Jai · Answer

substitute the value:
pH = -log[H+]
2.5 = -log[H+]
-2.5 = log[H+]
note that log has a base of. Thus to get [H+], raise both sides of equation by 10 (to cancel the log):
10^(-2.5) = [H+]
[H+] = 3.2 x 10^(-3)