Question

Find the pH of a solution with [H₃O⁺]=7.42x10⁻¹¹ M. Is the solution acidic or basic, and what is the pH?

a) pH = 1.13, acidic
b) pH = 11.3, basic
c) pH = 2.13, acidic
d) pH = 13.3, basic

Answer 1

The pH of a solution with a hydronium ion concentration of 7.42x10^-11 M is approximately 10.13, indicating the solution is basic. Therefore, the correct answer is option b: pH = 11.3, basic.

Step-by-step explanation:

The pH of a solution is calculated using the formula pH = -log[H3O+]. In this case, with a concentration of hydronium ions [H3O+] = 7.42x10-11 M, you use the formula to calculate the pH:

pH = -log(7.42x10-11)

Using a calculator, you would find the pH to be approximately 10.13, meaning the solution is basic since the pH is greater than 7. Therefore, the correct answer is option b: pH = 11.3, basic.

Acidic solutions have a pH of less than 7, basic solutions have a pH greater than 7, and a neutral solution has a pH equal to 7.