0.062 mol NaF + 127 mL 0.0399 M HF buffer pH

A buffer is prepared by

dissolving 0.062 mol of sodium fluoride

in 127 mL of 0.0399 M hydrofluoric acid.

Assume no volume change after NaF is added.

Calculate the pH of this buffer.

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> HF의 Ka = 6.8×10^(-4)

(0.0399 mol/L) (127/1000 L)

= 0.0050673 mol HF

Henderson-Hasselbalch 식

pH = pKa + log([짝염기]/[약산])

( 참고 https://ywpop.tistory.com/1926 )

= –log(6.8×10^(-4)) + log(0.062 / 0.0050673)

= 4.26

( 참고: 몰농도 대신 몰수 https://ywpop.tistory.com/13452 )

답: pH = 4.26

[키워드] HF 완충용액의 pH 기준, HF 완충용액 기준