Chapter 15, Problem 115CWP

Consider a buffered solution containing CH₃NH₃Cl and CH₃NH₂. Which of the following statements concerning this solution is(are) true? (K_a for CH₃NH₃⁺ = 2.3 × 10⁻¹¹.)

a. A solution consisting of 0.10 M CH₃NH₃Cl and 0.10 M CH₃NH₂ would have a higher buffering capacity than one containing 1.0 M CH₃NH₃Cl and 1.0 M CH₃NH₂.

b. If [CH₃NH₂] > [CH₃NH₃⁺], then the pH is larger than the pK_a value.

c. Adding more [CH₃NH₃Cl]to the initial buffer solution will decrease the pH.

d. If [CH₃NH₂] < [CH₃NH₃⁺],then pH < 3.36.

e. If [CH₃NH₂] = [CH₃NH₃⁺], then pH = 10.64.