Respuesta :
Answer: The pH of resulting solution is 8.7
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}[/tex]
- For TRIS acid:
Molarity of TRIS acid solution = 0.1 M
Volume of solution = 50 mL
Putting values in above equation, we get:
[tex]0.1M=\frac{\text{Moles of TRIS acid}\times 1000}{50mL}\\\\\text{Moles of TRIS acid}=0.005mol[/tex]
- For TRIS base:
Molarity of TRIS base solution = 0.2 M
Volume of solution = 60 mL
Putting values in above equation, we get:
[tex]0.2M=\frac{\text{Moles of TRIS base}\times 1000}{60mL}\\\\\text{Moles of TRIS base}=0.012mol[/tex]
Volume of solution = 50 + 60 = 110 mL = 0.11 L (Conversion factor: 1 L = 1000 mL)
- To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:
[tex]pH=pK_a+\log(\frac{[salt]}{[acid]})[/tex]
[tex]pH=pK_a+\log(\frac{[\text{TRIS base}]}{[\text{TRIS acid}]})[/tex]
We are given:
[tex]pK_a[/tex] = negative logarithm of acid dissociation constant of TRIS acid = 8.3
[tex][\text{TRIS acid}]=\frac{0.005}{0.11}[/tex]
[tex][\text{TRIS base}]=\frac{0.012}{0.11}[/tex]
pH = ?
Putting values in above equation, we get:
[tex]pH=8.3+\log(\frac{0.012/0.11}{0.005/0.11})\\\\pH=8.7[/tex]
Hence, the pH of resulting solution is 8.7
