Calculate the volume of 0500 M C2H3O2H and 0500 M C2H3O2Na r

Calculate the volume of 0.500 M C2H3O2H and 0.500 M C2H3O2Na required to prepare 0.100 L of pH = 5.00 buffer with a buffer strength of 0.100 M. The pKa of C2H3O2H is 4.75.

Calculate the volume of 0.500 M C2H3OH and 0.500 M CH3O-Na required to prepare 0.100 L of pH = 5.00 buffer with a buffer strength of 0.100 M. The pKa of C2H302H is 4.75. C2H302H: Number C2H3O2Na: Number

Solution

Let volume of C2H3O2H = x L

volume of C2H3O2Na = (0.100 - x) L

moles of  C2H3O2H = 0.500 * x = 0.500x mole.

moles of  C2H3O2Na = 0.500 * (0.100 - x) mole.

This is buffer solution,

so

PH = PKa + log [salt] / [acid]

5.00 = 4.75 + log [0.500 * (0.100 - x) / 0.500x]

(0.100 - x) / x = 1.778

x = 0.036 L

so volume of C2H3O2H = 0.036 L

volume of C2H3O2Na = 0.100 - 0.036 = 0.064 L