Calculate the ratio of CH3NH2 to CH3NH3Cl required to create a buffer with pH = 10.26.

Answer 1

pH = pKa + log [base] / [acid]

pH = 10.26

pKa for CH₃NH₃⁺ = 10.66 (Wikipedia)

10.26 = 10.66 + log [CH₃NH_2] / [CH₃NH₃⁺]

-0.40 = log [CH₃NH_2] / [CH₃NH₃⁺]

[CH₃NH_2] / [CH₃NH₃⁺] = 0.398

So ration of CH₃NH₂ to CH₃NH₃⁺ is 0.398 to 1