Question

A solution has a hydroxide ion concentration of 4.91 x 10^-5M. Answer the questions below for this solution:1. What is the pH of the solution? 2. Is the solution acidic, basic, or neutral?

Answer 1

Answer

1. The pH of the solution is 9.69

2. The solution is basic.

Explanation

What is given:

The concentration of hydroxide ion, [OH⁻] = 4.91 x 10⁻⁵ M

Step-by-step solution:

1. What is the pH of the solution?

The first approach to this question is to determine the pOH of the hydroxide ion concentration.

The formula to calculate the pOH of a solution is given as:

$pOH=-log[OH^-]$

Putting [OH⁻] = 4.91 x 10⁻⁵ into the formula, we have:

$\begin{gathered} pOH=-log(4.91\times10^{-5}) \\ \\ pOH=-(-4.31) \\ \\ pOH=4.31 \end{gathered}$

Finally, we can determine the PH of the solution using the relationship between pH and POH, which is:

$pH+pOH=14$

Putting pOH as 4.31, we have the pH of the solution to be:

$\begin{gathered} pH+4.31=14 \\ \\ pH=14-4.31 \\ \\ pH=9.69 \end{gathered}$

Thus, the pH of the solution is 9.69.

2. Is the solution acidic, basic, or neutral?

Since the pH of the solution is 9.69, then the solution is basic.

pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.