Answer:
pH = 10.93
Explanation:
To find the pH we need to use the Henderson - Hasselbalch equation:
[tex] pH = pKa + log(\frac{[A^{-}]}{[HA]}) [/tex]
Where:
[A⁻]: is the conjugate base of the acid = [CH₃NH₂] = 0.55 M
[HA]: is the acid = [CH₃NH₃Cl] = 0.29 M
Since the pkb of methylamine is 3.35, the pka is:
[tex] pk_{a} + pk_{b} = 14 [/tex]
[tex] pk_{a} = 14 - pk_{b} = 14 - 3.35 = 10.65 [/tex]
Now, the pH is:
[tex] pH = pKa + log(\frac{[A^{-}]}{[HA]}) = 10.65 + log(\frac{0.55}{0.29}) = 10.93 [/tex]
Therefore, the pH of the buffer solution is 10.93.
I hope it helps you!
