Final answer:
To find the pOH of a nitrous acid solution with a given H3O+ concentration, calculate the pH using the negative logarithm of the H3O+ concentration and then subtract the pH from 14 to get the pOH. In this case, the pOH is 5.59.
Step-by-step explanation:
To calculate the pOH of a nitrous acid solution that contains 3.9 × 10-9 M H3O+ at 25°C, we can use the relation pOH = 14 - pH. First, we need to calculate the pH of the solution by taking the negative logarithm of the H3O+ concentration.
pH = -log[H3O+] = -log(3.9 × 10-9) = 8.41
Now we use the pH to find the pOH:
pOH = 14 - pH = 14 - 8.41 = 5.59
The pOH of the nitrous acid solution is 5.59.
To calculate the pOH of a nitrous acid solution, we first need to calculate the concentration of OH- ions. Since nitrous acid (HNO₂) is a weak acid, it does not dissociate completely in water. However, we are given the concentration of H₃O+ ions, which is 3.9 × 10⁻⁹ M. Since water undergoes autoionization to produce equal concentrations of H₃O+ and OH- ions, the concentration of OH- ions is also 3.9 × 10⁻⁹ M. We can then calculate the pOH using the formula pOH = -log[OH-], where log is the common logarithm with base 10. Therefore, the pOH of the nitrous acid solution is approximately 5.59