Question

If the pH of a solution is 4.6, what is the [OH-] concentration in the solution?

a) 4.0 x 10⁻⁶ M
b) 4.0 x 10⁻⁸ M
c) 4.0 x 10⁻¹⁰ M
d) 4.0 x 10⁻¹² M

Answer 1

To find the [OH-] concentration in a solution with a pH of 4.6, we calculate the pOH (14 - pH) and then the [OH-] (10^-pOH). The pOH is 9.4, and the corresponding [OH-] is 4.0 x 10^-10 M, so the answer is c) 4.0 x 10^-10 M.

The write answer is b) 4.0 x 10⁻⁸ M

Step-by-step explanation:

The question asks to determine the hydroxide ion concentration ([OH-]) in a solution with a pH of 4.6. To find the [OH-] concentration, we must first calculate the pOH, and use the relationship that pH + pOH = 14.

Since the pH is given as 4.6, the pOH can be found by subtracting this value from 14 which gives us a pOH of 14 - 4.6 = 9.4. Next, we use the pOH to find the [OH-] concentration by taking the inverse logarithm (antilog) of negative pOH which is 10-9.4.

The calculation should give us [OH-] = 10-9.4 M. To find the closest answer choice, we convert this to standard scientific notation, which results in [OH-] = 4.0 x 10-10 M. Therefore, the correct answer choice is c) 4.0 x 10-10 M.

The write answer is b) 4.0 x 10⁻⁸ M