What is the pH of the final solution? ?

A buffer solution is made by adding 75.0 g sodium acetate (NaC2H3O2) to 500.0 mL of a

0.64 M solution of acetic acid (HC2H3O2). What is the pH of the final solution? Assume no volume change.

2 Answers

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  • 1 month ago

    Moles = mass/molar mass

    Moles of NaC2H3O2 = 75/82=0.88 mol NaC2H3O2

    Moraity = moles/volume

    moles = molarity*volume(liter)

    Moles of Acetic acid = 0.64M*(500/1000)L=0.32 mol

    pKa of acetic acid = .

    According to Henderson Hasselbalch Equation

    pH = pka + log[salt]/[acid]

    pH=4.75+log[ NaC2H3O2]/[C2H4O2]

    pH=4.75+log(0.88/0.32)

    pH=5.19

  • 1 month ago

    You need to know the molarity of the NaAc:

    MV = mass / molar mass

    (x) (0.5000 L) = 75.0 g / 82.0337 g/mol

    x = 1.82852 M (keep some guard digits)

    Now, use the Henderson-Hasselbalch equation:

    pH = pKa + log [base / acid]

    pH = 4.752 + log [1.82852 / 0.64]

    pH = 4.752 + 0.456

    pH = 5.208 (round off more as you see fit)

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