Answer:
Molar concentration of [NaC₂H₃O₂] is 2.08M
Step-by-step explanation:
It is possible to find pH of the HC₂H₃O₂ / C₂H₃O₂⁻ buffer using H-H equation, thus:
pH = pKa + log₁₀ [C₂H₃O₂⁻] / [HC₂H₃O₂]
Where:
pH = 5.28
pKa is -log Ka: 4.74
[HC₂H₃O₂] = 0.60M -It is possible to use the 0.60M concentration because you will add the same volume of both [HC₂H₃O₂] and [NaC₂H₃O₂] solutions.-
[C₂H₃O₂⁻] = ?
Replacing:
5.28 = 4.74 + log₁₀ [C₂H₃O₂⁻] / [0.60]
0.54 = log₁₀ [C₂H₃O₂⁻] / [0.60]
3.47 = [C₂H₃O₂⁻] / [0.60]
2.08M = [NaC₂H₃O₂]
Molar concentration of [NaC₂H₃O₂] is 2.08M