Question

1. Calculation of pH. A weak acid HA (pKa = 4.85) reacted with strong base NaOH The reaction is HA + NAOH H20 + NaA. There are 100 mL 0.100 M HA solution, and the concentration of Na OH is 0.100 M. 0 moles a. What is the pH when 0.00 mL of NaOH is added to the 100 mL HA solution? 2 x1 les b. What is the pH when 20.0 mL of NaOH is added to the 100 mL HA solution? 91 mu OL m gle c. What is the pH when 50.0 mL of NaOH is added to the 100 mL HA solution? d. What is the pH when 80.0 mL of NaOH is added to the 100 mL HA solution? z.0lX= e.What is the pH when 100 mL of NaOH is added to the 100 mL HA solution? f.What is the pH when 150 mL of NAOH is added to the 100 mL HA solution?

Answer 1

Kaz 10 = 1048 1.4155 OM NOON+ - Ä ttt e o-loom I o X X 0-100 (neglect x as Ka<103) Kar Cá Cart] CHA) Luxios 2 x 2 z) x2 Crit) 2 J 1.4x650 100 2 0.0012 M pm tog (AT). Tog Co-oo12) 212-92 b.) neutralizatan 2 mmoles waoH 2 0-10om x 200ml a 2 mmoles 22k10 moles mmoles HA 2 0-loomx loomLa 10 mmoles. (in mnoles calculation HA & easy Naon - Nat +40 I 20mmoles 2 mnoles C -2 -2 +2 F & moles 2 mmole now solution contains weak auld, HA and conugate base e, so it acts as buther pn 2 plat 10g (Base) (yataal Cacid volume Cancel) 2.00 mmolestar 2 485+ log ( 25.0mmresius) (4-25

I Not +H2O HA & Noon lommoles Immoles Immoles f smoles log1 zo. pH a pica + 10 CAD 4-85+ log1 2) PH 14-85 har in equliedence) Point tirration d-) 440 + 4C HA & Naon → - commole) 8 mmoles -8 -8 tu al +8 pH = 485 + 10g (&) 215-45) HA traoh I THO 1 commoes 10mmoles o F O tlommory here only l present, calculate a acts as bove Ky a ko 1-01oty a Ky from xa as 7.1 x 100 TYxor CA2 inmoles Total A (nina) - o 100m x 100ml 2010 volume 2oomL 2 O. O Soom & [ 0-osoom O HA & on 60-000- neglect &

to t Сно) Coo) CA 7.1 x 1070 2 x² 0-05oom 2) × 2 Cont) 2 Jo-osoox7 1 8100 a 5.9 x 100m 2) 2) pon. por (5-9x100), 5.22 2 14-00-5-22 2 [8.78) 150mL naoy & excess 2 waoh Total mnoles - modes noor react with ha Total volume Cont) left 2 (woon) lerr o loom x 150m – o-loomx 100ml 250 ml Cort) 2 0.02oom 2) por a 10g [o.020) 2 1.70 - + H (-O --Po 1 12:30 from is negligible as it acts as weak bases Cort