Question

a solution is prepared by mixing 2.50 g of acetic acid (CH3CO2H, FW=60g/mol, Ka=1.75x10^(-5) with 4.70 g of sodium acetate (CH3CO2Na, FW=82g/mol) and adding water to a 500 mL volume. Note that sodium acetate yields Na+ and CH3COO-, the conjugate base of acetic acid.

a.) what is the pH?

b.) 15mL of 0.50 M HCl were added to the 500 mL solution, what is the pH after addituon of acid?

write answer to 3 sig. figured.

Answer 1

og 1 CH₂ C 2M] 4.76 + log 0.067 4 16 @ meter of Chicou = man = 2.50 g = 0.042 mol der how melarmare Gogmory meleg of NaCH₃ Co2 = 4.70g 0.057 me Segmat pka a legkah 2 og 1.75 X10-5 = 4.76 PM a pka + leg (Ng CH3C] i es choses on [CH₂ C2M) 0.057 0.042 - 4.89 (anqual 6 mdog of Hel added = volume (L) x melarity (melul) J = 0.015 L Xosom a 0.007smel moles of CH₂ Cezh a 0.842 md. melex of Na Chce = 0.057 mo NaCm C + Ас) - СИ, Ca, M + NaC/ I 0.057 mel 0.007smel 0.042 mel ci -0.0075 -0.0075 to.0075 E: 0.0495 o d 0.0495 pH = 4.76 tlg 0.0495 0.0995 = 4.76 langwel