help with 5 and 6 please 5. Choose the effective pH range of a HF/Naf buffer. For HF, Ka = 3.5 x 10-4 6. If a small...

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Question

5. Choose the effective pH range of a HF/Naf buffer. For HF, Ka = 3.5 x 10-4 6. If a small amount of a strong acid is added t

help with 5 and 6 please

Answer 1

Answer #1

Q5:

Buffer capacity is maximum when pH = pKa i.e. [NaF] = [HF]

pKa = - log(3.5×10^-4) = 3.456

Effective pH range of NaF/HF buffer = pKa $\pm$ 1

= 3.456 -1 to 3.456+1

= 2.456 to 4.456

Effective pH range = 2.46 - 4.46 (Answer)

Q6 :

H⁺(from strong acid) + A^-(from buffer solution) $\rightarrow$ HA (an weak acid ) ---buffer action .

(b) the strong acid reacts with A^-to give HA, which is weak acid . (Answer)

Answer 2

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