Answer:
pH range = 2.74-4.74
Explanation:
The pH range of a buffer falls in between one unit on either side of pKa.
The given weak acid is HF and its Ka = 1.8X10⁻⁴
pKa = -log(Ka)
pKa = -log(1.8X10⁻⁴)
pKa = 3.74
The pH range is 3.74-1 = 2.74 to 3.74+1 =4.74
pH range = 2.74-4.74
