The titration curve for the titration of 0.100 M Na₂CO₃(aq)with 0.100 M HClO₄(aq)is: Estimate pK_b1.

Question

Quizplus · Accepted Answer

The equivalence point of the titration is at pH 7. At this point, all of the HClO has reacted with Na₂ to form NaClO and H2O, and the solution contains NaClO and its conjugate base ClO- in equal concentrations. Therefore, the pH is equal to the pKa of the ClO- ion, which is 3.7. Since pK_b1 is the negative logarithm of the dissociation constant of H₂CO- , which is a weaker acid than ClO-, its pK_b1 value will be higher than 3.7. The only answer choice that fits this criterion is C (3.7 is likely too low for pK_b1).

The Titration Curve for the Titration of 0