The of hydroxylamine, , is . A buffer solution is prepared by mixing 120 of a 0.34 hydroxylamine solution with 60 of a 0.25 solution.Solve for the PH
To solve for the pH of a buffer solution, we need to determine the concentrations of the acidic and basic components of the buffer and apply the Henderson-Hasselbalch equation.
In this case, we have two components in the buffer solution: hydroxylamine (NH2OH) as the weak base, and its conjugate acid, hydroxylammonium (NH3OH+). The hydroxylamine solution has a concentration of 0.34 M, and the hydroxylammonium solution has a concentration of 0.25 M.
Step 1: Calculate the moles of hydroxylamine and hydroxylammonium:
Moles of hydroxylamine = concentration × volume
Moles of hydroxylamine = 0.34 M × 0.120 L = 0.0408 mol
Moles of hydroxylammonium = concentration × volume
Moles of hydroxylammonium = 0.25 M × 0.060 L = 0.015 mol
Step 2: Calculate the total volume of the buffer solution:
Total volume = volume of hydroxylamine + volume of hydroxylammonium
Total volume = 0.120 L + 0.060 L = 0.180 L
Step 3: Calculate the concentrations of hydroxylamine and hydroxylammonium:
Concentration of hydroxylamine = moles/volume
Concentration of hydroxylamine = 0.0408 mol / 0.180 L = 0.227 M
Concentration of hydroxylammonium = moles/volume
Concentration of hydroxylammonium = 0.015 mol / 0.180 L = 0.083 M
Step 4: Apply the Henderson-Hasselbalch equation:
pH = pKa + log10([A-]/[HA])
The pKa of hydroxylamine (NH2OH) is 6.15. We can calculate the ratio [A-]/[HA] as [hydroxylammonium]/[hydroxylamine].
pH = 6.15 + log10([0.083 M]/[0.227 M])
pH = 6.15 + log10(0.365)
Using a scientific calculator, the log10(0.365) is approximately -0.437.
pH = 6.15 + (-0.437)
pH = 5.713
Therefore, the pH of the buffer solution is approximately 5.713.