A 0500 G Sample of an Unknown Substance Was Titrated with with a 0.1

Multiple Choice

A 0.500 g sample of an unknown substance was titrated with a 0.1 M HCl solution. Another 0.500 g sample of it was titrated with a 0.1 M NaOH solution. The resulting titration curves are illustrated here. Given the following possibilities, what is the sample?

A) Na₂CO₃
B) NaHCO₃
C) H₂CO₃
D) CO₂
E) There is no way to tell.