What is the pH of a solution with [OH-] = 2.5 x 10-3?
I don't even know where to begin with this problem :(
You know [OH] + [H+] = 1*10^-14
so solve for [H+], then pH= -log [H+]
To solve this problem, you need to use the relationship between the hydroxide ion concentration ([OH-]) and the hydrogen ion concentration ([H+]) in a solution. In an aqueous solution, the product of [OH-] and [H+] is always equal to 1.0 x 10^-14 at room temperature, which is commonly referred to as the autoionization constant of water:
[OH-] * [H+] = 1.0 x 10^-14
In this problem, you are given the hydroxide ion concentration ([OH-]) which is 2.5 x 10^-3. To find the hydrogen ion concentration ([H+]), you can rearrange the equation as follows:
[H+] = 1.0 x 10^-14 / [OH-]
[H+] = 1.0 x 10^-14 / (2.5 x 10^-3)
Calculate the value using a calculator or by dividing the two numbers:
[H+] = 4 x 10^-12
Now that you have the hydrogen ion concentration, you can calculate the pH. The pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration. Use the formula:
pH = -log [H+]
pH = -log (4 x 10^-12)
Find the logarithm of the number using a calculator:
pH ≈ 11.4
Therefore, the pH of the solution with a hydroxide ion concentration of 2.5 x 10^-3 is approximately 11.4.