0.12 M C6H5COOH + 0.20 M C6H5COONa buffer pH

0.12 M C6H5COOH + 0.20 M C6H5COONa buffer pH

0.12 M benzoic acid와 0.20 M sodium benzoate로

이루어진 완충용액의 pH를 계산하라.

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> Ka for benzoic acid is 6.3×10^(-5)

---> pKa = –log(6.3×10^(-5)) = 4.2

Henderson-Hasselbalch 식

pH = pKa + log([짝염기]/[약산])

( 참고 https://ywpop.tistory.com/1926 )

= 4.2 + log(0.20 / 0.12)

= 4.42

답: pH = 4.4

[키워드] 벤조산 완충용액의 pH 기준