We’re being asked to calculate the ratio [NH3]/[NH4+] in ammonia/ammonium chloride buffered solutions for ph 9.00.
In an ammonia/ammonium chloride buffered solution, ammonia, NH3 is the weak base and the ammonium ion, NH4+ is its conjugate acid.
Recall that for buffers the pH can be determined using the Henderson-Hasselbalch equation:
[NH3] = concentration of the weak base, NH3
[NH4+] = concentration of conjugate acid, NH4+
Since we're given the pH, we can solve for the ratio: [NH3]/[NH4+]
But first, we need to determine Ka, Since ammonia is a weak base:
Kb = 1.76 x 10-5 (can be found in textbooks or online)
Recall that we can solve Ka from Kb using the equation:
**Kw = 1.0 x 10-14 at 25°C (value can be found in textbooks or online)
Calculate the ratio [NH3] / [NH4+] in ammonia/ammonium chloride buffered solutions with the following pH values:
a. pH = 9.00
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