A sample of orange juice is found to have a PH of 3.80. What is the concentration of the hydroxide ion in the juice?
Answer Details
The pH scale measures the acidity or basicity of a solution. The pH is defined as the negative logarithm (base 10) of the concentration of the hydronium ion (H3O+), which is given by the expression:
pH = -log[H3O+]
To calculate the concentration of the hydroxide ion (OH-) in the juice, we need to use the equation for the ion product of water:
Kw = [H3O+][OH-] = 1.0 × 10-14
where Kw is the ion product constant of water. At 25°C, Kw has a value of 1.0 × 10-14.
To solve for [OH-], we need to rearrange the equation:
[OH-] = Kw / [H3O+]
Now we can substitute the pH of the orange juice to calculate the concentration of hydronium ion [H3O+].
pH = -log[H3O+]
3.80 = -log[H3O+]
[H3O+] = 10^(-3.80)
[H3O+] = 1.58 × 10^(-4) mol/L
Substituting this value into the ion product equation:
[OH-] = Kw / [H3O+]
[OH-] = 1.0 × 10^-14 / (1.58 × 10^-4)
[OH-] = 6.33 × 10^-11 mol/L
Therefore, the concentration of the hydroxide ion in the orange juice is 6.33 × 10^-11 mol/L.