Respuesta :
Answer:
0.692
Explanation:
To solve this problem we can use Henderson-Hasselbach's (H-H) equation:
- pOH = pKb + log [tex](\frac{[NH_4Cl]}{[NH_3]})[/tex]
In which pOH can be calculated from the pH:
- pOH + pH = 14
- pOH = 14 - pH = 14 - 9.09
- pOH = 4.91
Then we use the H-H equation to calculate[tex]\frac{[NH_4Cl]}{[NH_3]}[/tex]:
- 4.91 = 4.75 + log [tex](\frac{[NH_4Cl]}{[NH_3]})[/tex]
- 0.16 = log [tex](\frac{[NH_4Cl]}{[NH_3]})[/tex]
- [tex]10^{0.16}[/tex] = [tex]\frac{[NH_4Cl]}{[NH_3]}[/tex]
- [tex]\frac{[NH_4Cl]}{[NH_3]}[/tex]= 1.44
As the problem asks for the ratio of ammonia to ammonium chloride, we invert [tex]\frac{[NH_4Cl]}{[NH_3]}[/tex]:
- [tex]\frac{[NH_3]}{[NH_4Cl]}=\frac{1}{1.44}[/tex] = 0.692
The mole ratio of ammonia to ammonium chloride in a buffer with a pH of 9.09 is 0.692.
How we write Henderson Hasselbalch equation?
Henderson Hasselbalch equation for the weak base (NH₃) and for their conjugate acid (NH₄Cl) will be written as:
pOH = pKb + log[NH₄Cl]/[NH₃], where
pKb = base dissociation constant = 4.75
pOH will be calculated from the given value of pH as:
pH + pOH = 14
pOH = 14 - 9.09 = 4.91
Now we these values in the above equation and we get,
4.91 = 4.75 + log[NH₄Cl]/[NH₃]
log[NH₄Cl]/[NH₃] = 0.16
[NH₄Cl]/[NH₃] = 10⁰°¹⁶
[NH₄Cl]/[NH₃] = 1.44
[NH₃]/[NH₄Cl] = 1/1.44
[NH₃]/[NH₄Cl] = 0.692
Hence, required mole ratio is 0.692.
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https://brainly.com/question/26746644