Question

Calculate the pH after 4.0 mL of 0.50 M NaOH is added to 110.0 mL of a buffer made of 0.40 M CH3COOH and 0.50 M NaCH3COO. The Ka of acetic acid is 1.8 x 10.

Answer 1

first to calculate the moles of each.

then we find moles of NaOH added.

it react with acid.

then to find the moles of acid CH3COOH left.

then to find Molarity in total volume.

then to calculate pH.

Solm Tom Giren, [C13200 1] = 0.4m. Duffes. - [NA Cuzc007 = 0.5M Ku 18x10-5 Jwitiat pt = pta Flog den.com - 5-109[1-8810-5) +loglia p"=14.39] now, moles of [C 4₂ 2001 = 0 y not xoolol. = 0.844 mol. u 'Ch2200 - > 0.5 mol x 0.1104 = 0.035 mod. mols of Na ou adeled o Lx0.5mol = 0.002 acid react with Naou. this moles of chocoon = 0.044 -0.002=0.042 moles of Ch₂200 = 0.055 mol. Page No. O

to calulute molarity in total volue = 110 + 4 mL = 0.114L. ch₂coon = 0.04&mol 0 8 0.3684M o-lYL C4₃COO- 0.055 nol = 0.4825 m proptera + log teksto o log (1.8*10-s) + log (0-9825) p" -14.867