Question

WS #7 3) To the buffer prepared in Question 2 is added 75.0mL a 0.375 M HCl solution. What is the resulting buffer? cgpts) рное the 4) The buffer capacity is reached when the pH of the buffer shifts by 1.00pH unit. What volume of a 1.OOM NAOH Solution would need to be added (fresh) MOAB-H/M DAB-Na solution to reach this point? (&pts

Answer 1

Solution (3) Volume of Buffer solution is required molasity of buffer solution is required Solution (W volume and molarity of buffer solution is required unknown assumed that Selestion ④ aud is mono protic acid; HA+ Naon - Nat Át H2O moles of Naon = molasity Volume 0.1750 M X 39.45 ml x L 10ooml = 0.00690 mol From the stoichio metry of reaction maly of Acid 0.00690 mal. moles of Naod Il

moles of salt formed = males of woon 0.00 690 mal total volume of solistion = 25 ml +39.45 ml. .64.45 ml. moles Molasity of fall Volume 0.0069o mol 6445 m2 XIL 16ooml 0.107 11 m pH of salt solution is given by pn = 7+ 2 pka + log С when c = molarity of salt. & log (0.10.711) 9.86 7 + 1/2 pka + 9.86-7 = & pka + } * (-0.970) 2.86 1 pka 0.495 pka = 6.69 pka of Acid z6.69

moly of Acid = mass of Acid O molar mass molar mass mass of Acid males of Acid 1.486 g 0.00690 mal 215.36 g/no Molecular weight of mel Acid