Question

The half-equivalence point of a titration occurs half way to the end point, where half of the analyte has reacted to form its conjugate, and the other half still remains unreacted. If 0.300 moles of a monoprotic weak acid (Ka = 6.3 × 10-5 M) is titrated with NaOH, what is the pH of the solution at the half-equivalence point?

Answer 1

Use the henderson-hasselbach reaction

Answer 2

pH = pKa

Answer 3

pKa = -log(6.3x10^-5)

Answer 4

pKa = 5-log(6.3)

uhhhhh...... 5 - Log2+Log3
ummmm.....5 - (0.3)+(.48)
ooooooo......5 - (0.78)
pH = (roughly) 4.22