Calculate the pH of a blood plasma sample...?

Calculate the pH of a blood plasma sample with a total  CO2 concentration of  

25.6mM and bicarbonate concentration of 24.5 mM. The relevant  pK of carbonic acid is 6.1.

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  • Fern
    Lv 7
    4 weeks ago

    total CO2 = 25.6 ; [HCO3-]= 24.5

    then conc. of H2CO3 is (25.6 - 24.5) = 1.1

    pH = 6.1 + log[HCO3-]/[H2CO3]

    pH = 6.1 + log(24.5/1.1)

    pH = 6.1 + log(22.27)

    pH = 6.1 + 1.3 = 7.4

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  • 4 weeks ago

    Henderson-Hasselbalch to the rescue!!

    pH = pKa + log [acid / base]

    pH = 6.1 + log [25.6 / 24.5]

    pH = 6.1 + 0.01907

    pH = 6.12

    Which would round off to 6.1

    • Bo4 weeks agoReport

      Isn't it pH = pKa + log [base]/[acid]?  If not, why not?

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