Question

When titrating 25.0 mL of 0.080 M HClO with 0.060 M NaOH, calculate the pH after adding 25.0mL of 0.050 M NaOH (pKa = 7.55).

A. 7.43

B. 7.55

C. 7.77

D. 10.08

E. 12.48

Answer 1

Heio is weak acid and ok as 7.55. Basa is titrated with Helo Now, when Ne strong base Naou (salt) is Naoh then equinolar amount of produced. Helo Nadh + Na o a 4 * H2O acid basa salt initial O fO.M 8. 0.052 050 M final 0:080 -0.050 0050 M o.030M concentration of the acid it in the souition,

Citerol ? Moles of acid in solution Total volume of the soution 25.0 ml. x6.080 M 25.0 mix o-050 M 2 (25.0+ 2.5.0 mL 015 M concentration of the salt in the solution [Nadel) (NaOH) 25-0 onha 50 (25.0 +25.0) ma M 0.025 M. Now the solution contains Deak arid and its salt, hence the will act as a lou buffer solution. the pH of According to Henderson-tasselbalch equation the buffer solution solution is given by. hopH. I oko + log Sool [Naou] (Hoel 0.025 7.55 t log 0.015 2 Com :) 7.77

So the correct option is (C) 7.77