Question

Part B: Titration of a weak base with a strong acid Pipette 25.00 mL of 0.1 M (record the exact molarity) ammonia into a clean 400 ml beaker after first placing a magnetic stirring bar on the bottom of the beaker. Add ~150 mL of deionized water and 2 drops of the indicator methyl red. Place the beaker on the magnetic stirrer. Lower the electrode into position, approximately one inch above the bottom of the beaker. Obtain ~60 mL of an unknown HCl solution (for part B) from the front bench. After rinsing a burette, fill it with unknown HCl and prepare it for titration. Place it in position to titrate the HCl solution into the ammonia solution. Read and record the burette reading and pH, both to two decimal places. Add HCl solution to the base slowly. Initially take burette and pH readings after every 2.00 - 3.00 mL addition. As the equivalence point approaches the pH will drop more rapidly; add smaller (~ 0.10 mL) volumes of HCl before each pH reading. Start to reduce the volume of each titrant addition at a pH of approximately 8.5. Note the volume at which the indicator changes colour. Carry the titration beyond the endpoint, continue with small volume additions until the pH plateaus* and note how pH changes in this region (add 40.00 mL HCl in total). (* when the pH is changing only in the second decimal place, you have reached a plateau)

Help, how to graphically find the equivalence point volume for the titration of NH3 + HCl

NH3 actual concentration is 0.098M

Answer 1

a NH3 Salation o i Point of inflexation, pH change indicating - completion of fitratto on Hel Solution. of 5 10 is 20 25 30 35 40 45 . - volume of Hel.. Hel of Notty > Nath el , . At point of inflexation huge change of pot occurs because all why contain in. Solution Completly transforms into the wheel. So, there is a huge change in put from A Basie po (37) to the lige acidie pH (<3). Point of inflexation Endieating the completion of titration. To fall Nha is consumed by Hel. So, Both are Present in same Amount (salt form). In picture, the point of inflexition obrewed at Volume of Hel=25.2 me. . So, YS, 2 Vq S2 v= 25m2 = valence of Nis ,.. 2 Ginen By – Strengter of Noz on Sq z Ni s, 0.09800M V2 2 " w her Waz 25.2m Szz Sprungen u hee. 125201098) ? 2527" 20.0972M [ Please like and comment. Thank you.