Answer :
Final answer:
To find the pOH of a 0.166 M perchloric acid solution, one would need to calculate the pH from the concentration of H+ ions and subtract it from 14 to get the pOH. However, the question's information does not allow us to select a correct answer from the given options, and the correct pOH calculation should reflect that perchloric acid is a strong acid with full dissociation in water. Therefore correct option d) 1.64
Explanation:
To calculate the pOH of a 0.166 M solution of perchloric acid (HClO4), which is a strong acid, we need to understand that it dissociates completely in aqueous solution. This means that the concentration of H+ ions will be the same as the initial concentration of perchloric acid. Since the concentration of H+ is 0.166 M, we can use this to find the pH, and subsequently the pOH.
The pH is calculated using the formula pH = -log[H+]. So, pH = -log(0.166). Once we have the pH, we can find the pOH since pOH + pH = 14 (at 25 degrees Celsius). A pH of 0.78 corresponds to a pOH of 14 - 0.78 = 13.22, but this is not a realistic value for a strong acid like perchloric acid. Since there's no calculation in the query resembling the options, and the values given in the examples are not applicable, a correct calculation should be performed.
Given that the pH of the 0.166 M solution of perchloric acid has to reflect complete ionization and the formula pH + pOH = 14, we ought to assume a strong acid will have a very low pH and consequently, a very high pOH. However, without doing the exact calculation here, we cannot select from the provided answers accurately.