Answer to Question #337700 in Chemistry for als

Question

What is the [H3O+ ] of 1.0 M  HF mixed with 1.0 M NaF. Ka = 6.6 x 10-4

Answer 1

Solution:

The Henderson-Hasselbalch equation is commonly used to calculate the pH of a buffer solution from the concentration of the buffer components:

where pK_a is the acid dissociation constant and [base] and [acid] are the base and acid concentrations, respectively.

base = NaF

acid = HF

Therefore,

pH = −log(6.6×10^−4) + log(1.0 / 1.0) = 3.18 + 0 = 3.18

pH = 3.18

pH = −log[H₃O⁺]

Therefore,

[H₃O⁺] = 10^−pH = 10^−3.18 = 6.6×10^−4

[H₃O⁺] = 6.6×10^−4 M

Answer: [H₃O⁺] = 6.6×10^−4 M