Question

4. (a) Sketch an approximate titration curve for the titration of an NaOH solution with standard HCl solution. Briefly explain the shape of the curve before the equivalence point, at the equivalence point, and after the equivalence point. Chapter 4: Monitoring Acid-Base Titrations with a pH Meter (b) What would the pH be at the equivalence point of the titration in (a)? Briefly explain.

Answer 1

• Titration of bct vs Naolt a) This is a titralian of strang acid with strong base. [both S (HD Ifcrt Naon naut H2ol [ Aftor equivalence point. wwe utauwe PWE -- MINIT - - Equivalence point (rapid change in pH ) duc to neutralisatian/ of all Ht by oh- Na [volat acid = volat alkali] S volume at alkali added- Besare cquuvalence point => Here initially there is anly Hel in the medium. Hence the PH of the medium will be pH of the acid. pH = -lcy [H+] => Then after adding venu vo mlak base to the vamlot, acid [vo <va] Teri = pkatlay Na -VES voys T r salti I Acid] - The strang base V6 ml will react with no ml of acid to favem Vo mi at salt. Hence the PH will be still acitic. => Hence remaining acid (va-V0)xs [ 24* m01/LP - molt - Edris is Henderson-Hasseltaleh equatioun. Sauna At the equivalence point At the equivalance paint, the vaml of S(N) bare will react and neutraline va ml of SCN) acid. Hence there will be no excess H&/ohol in the meticum. The metium will be neutral. The pH will be 7.0. Stream

=) As all the Ht and all the Ht and oh has reacted to farm H2O, the change in pH 1. Aftex the equiva is very high. . The small amount of addeitian as base will change the PH fram the acitic paint to the baric paint through the equivalance paint, as the titraitian is nearequivalence paint. The change in pH in very aggressive, which is a hawn in the curre. After the equivalence point Additian of excess bare will make the medium basic as there un no acid, the PH at the base will determine the pH ar the metium. [PH = 14 - POH [POH = -log [OH-]] => Adteitian of marc tase will make the medium mare basic. IN:B - During the calculatian of PH befare the equivalence paint, the, valume if in given in mi. gfcen important to canvert it to Lt's by divideing with 1000. [H4) = (va-Vo) XS(M) [ as 1000 mb > 1447 (M-> Motory 1] [salt] = Vb XSCM) - PH = pka tay ra ba us] Tooo 1000 . apka tay Lu rol b) The pH-at the equivalence is f. Because mole of Ht=molcs ROH . The solutian is neutralized.