The PK_a of Acetic Acid, HC₂H₃O₂, Is 4

Multiple Choice

The pK_a of acetic acid, HC₂H₃O₂, is 4.76. A buffer solution was made using an unspecified amount of acetic acid and 0.30 moles of NaC₂H₃O₂ in enough water to make 1.50 liters of solution. Its pH was measured as 4.50 on a meter. How many moles of HC₂H₃O₂ were used?Hint: The opposite operation of log(x) is 10^x.

A) 0.31 mol
B) 0.55 mol
C) 0.61 mol
D) 1.09 mol
E) 1.21 mol