Question

6) A 35 mL solution of 0.241 M HCl is titrated with 0.127 M NaOH: a) How many milliliters of NaOH solution are required to reach the equivalence point? b) What is the pH at the midpoint of the titration? c) What is the pH at the endpoint of the titration?

Answer 1

HCl is a monobasic acid and NaOH is a mono acidic base.

when At equivalence point, Number of moles of aled = No of moles of base Soluron in ML Number of moles of bare & Molarity xvolume of (ooo Given that Molarily & Nacht -0.127 M Molarity of Hel = 0.2419 Volume of Hal. 35 mL 0.241 M X 35mL 0.127M X v in ml tooo 1000 0.241 M X 35.ml 0.127 M volume of book? required 66.42 mL - 66.4mL 6) At midpoint of tilrahon, 33.2 mL of 0.127 M NaOH i added It in, molar V, me of acid is mixed with M. Moler ņmL of bar, the concentration of resultant Soluhon is M = Mivi - Mz ve Vitve if Miv, J Me Y & Soluhon i acidic

35 ML X 0.241 -0.127M X 33.g. 35+33.2 5 0.06185M = 0.0619 M Concentration of acid (Hel) after addehon of 33.2 mL of 0.127M NaOH : ( Hell = 0.0619 M Hel - Httor 0.0619 0.0619 (4*) - 0.0619 M p4--1g (H+) = -109,60.0619) = 1.208 = 1.21 (tel) - At end point, att acid is completely neutralised & only bare (NaOH) is present. Concentrahon of base = 0.127M. [NaOH = 0.127 M. (OH) = 0.1279 (NoHNetto) polt – log Colt] = -log (0.127) = 0.896 20.9 finca pH + pot = 14 pH ly-pol=14-019 13.1