Calculate the pH of a buffer that is 0.080 M HF and 0.040 M NaF.The K_a for HF is 3.5 × 10^-4. A) 2.06 B) 4.86 C) 3.16 D) 3.56 E) 3.76

Question

Quizplus · Accepted Answer

First, we need to calculate the pKa of HF: 
pKa = -log(Ka) 
pKa = -log(3.5 × 10^-4) 
pKa = 3.46

Next, we need to use the Henderson-Hasselbalch equation to calculate the pH of the buffer: 
pH = pKa + log([A^-]/[HA]) 
pH = 3.46 + log(0.040/0.080) 
pH = 3.16

Therefore, the pH of the buffer is 3.16, which is option C.

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