Question

14. Calculate the pH that results when the following solutions are mixed together. Assume that the total volume after mixing is 200.0 ml. (1) 35 ml. of 0.20 M formic acid, HCO2H (The Ka value of formic acid is 1.8 x 10-4..) (2) 55 mL of 0.10 M sodium formate, NaCO2H (3) 110 mL of water (a) 3.64 (b) 3.11 (c) 4.58 (d) 3.39 (e) 4.20 I 15. After mixing the solution in problem #14,50.0 mL of 0.10 M NaOH is added to the entire 200 mL of the solution. The new pH of the solution is: (a) 4.46 (b) 3.74 (c) 7.00 (d) 9.40 (e) 5.25

Answer 1

NOH MAMS For a buffer sal pH = Pha + log! Al ating FON А NIS, V232 S2 ? 55*0.1 (110 +55) 0.034 [A-] 1658 0.034 2 200 a 0.028 For НА, Nis, V282 S 2 - 35x0.2 145 0.048 [HA] 145 x 0.048 0.0348 200 Н - log (1.8x154) + log 0.028 0.0B48 3.745 -0.0944 3.65 M 3.64 Ans ca). Addition of some o.1 naon means formation of Ma CO₂H e total sal become • 105 me o.IM 250 then [ A ] 105 X 0.1 S2 110 + 55+30 20.0488

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