Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?

a. 4.0M c. 10^-4M

b. 10^-10M d. 10^4M

c. 10^-4M

Explanation:

pH measures the concentration of H + ions in a solution. It's a scale and the value ranges from 1 to 14. 7 is a neutral pH, below 7 is acidic and more than 7 is basic.

pH = - log[H+] where [H+] = hydrogen ion concentration in Molarity (M)

Given pH = 4 so,

4 = - log[H+]

[H+] = antilog (-4) = 10^-4 M

Hence, hydrogen ion concentration of lake = 10^-4 M