Question

Calculate the hydronium ion concentration in an aqueous solution that contains 2.50 × 10^(-2) M in hydroxide ion.

Option 1: 6.00 × 10^(-12) M
Option 2: 4.00 × 10^(-11) M
Option 3: 2.50 × 10^(-2) M
Option 4: 4.00 × 10^(-12) M

Answer 1

To find the hydronium ion concentration given the hydroxide ion concentration, use the ion product constant for water, Kw, and divide it by the hydroxide ion concentration. The correct hydronium ion concentration, with the given hydroxide ion concentration of 2.50 × 10-2 M, is calculated to be 4.00 × 10-13 M.

Step-by-step explanation:

To calculate the hydronium ion concentration in a solution based on a given hydroxide ion concentration, we can use the ion product constant for water, Kw, which is 1.0 × 10-14 M2 at 25 °C. This constant represents the product of the concentrations of the hydronium ions [H3O+] and the hydroxide ions [OH-].

Using the formula Kw = [H3O+][OH-], and knowing that the hydroxide ion concentration is 2.50 × 10-2 M, we can rearrange the formula to solve for [H3O+]:

[H3O+] = Kw / [OH-]

Substituting the values:

[H3O+] = (1.0 × 10-14) / (2.50 × 10-2)

[H3O+] = 4.00 × 10-13 M

Thus, the hydronium ion concentration is 4.00 × 10-13 M, which makes Option 2: 4.00 × 10-11 M the closest correct option provided, albeit not accurately matching the calculated value.