Question

Benxoic acid, C₇H₅O₂H is a weak monoprotic acid (Ka = 6.3 * 10^-5). Consider a titration between 20.0 mL of 0.100M benzoic acid solution with 0.200 M sodium hydroxide, NaOH.

a.) What volume of NaOH is required to reach the equivalence point?

b.) Calculate the pH of the solution at equivalence point

Answer 1

cy H, H: molarity = 0.1M | ka= 6-3 XL05 . volume arom1=0.02L Loka_-log ka = -log (6-3) pkaa 4.2 1 pkW 214 719=-109 (6-38105) / no of moles = 0.280002 0-002 at equivalence Roint moles of çito H = moles of Naslt -0-002 moles of Nach molarity of Nasta - volume of Naolt 0.002 - volume of vagt 0-22 volume of Nagtao olba toml & Hs 2H+ Naol - {HsQ Natto - strong bose salt weakacid 0.002 0.002 1-0-002 to-ool. 0-02 e l-o-ooz -- 10-02 tool 20-03 L 0-02 torola Total volume a n. 0-002, 30.06667M?[C [elts & Na] = 2 = 0.03 For this salf pH fromula pH = 2 Eplew tokatloge] pt = z[14+4-2 tlog 20.06867)] pH = 8.512

pH formula's for salt's weak acid + strong base ->salft iho pH = Ź [pew tpka + loge] strongacid & weakbase salf to a pH = ₃ [ pkW _pke_loge]