Question

Physiological Chemistry Laboratory II - SPRING 2020 8. Calculate the unknown mass of a sample of KHP (204 22 a/mol) if it consumed 39.27 mL of a 0.5094 Min solution to reach the phenolphthalein end point. 9. If 28.75 ml of 0.2055 M HCl are required to reach the end point of a titration of a 46.93 ml sample of NaOH, what is the molarity of the NaOH solution? What if the acid was phosphoric acid, H3PO4? 10. Titration of 25.00 mL of a monoprotic acid solution with 0.2269 M NaOH is shown below: initial NaOH volume reading of buret = 3.96 ml. final NaOH volume reading of buret = 38.84 mL Based on the data above what is the molar concentration of the acid in the solution?

Answer 1

8) Calculation of unknown mass of a sample of KHP Molar mass of KHP = 204:22 9 mol' KHP sample consume 39.27 mL of 0.5694 M NACH we know, Viso = 0232 oi Amount of KHP = 39.27 mL X0.5694 M = 39.27 xvo-> Lit x 0.5094 mol = 0.0223 moli 1 mol KHP = 204.22 8 050223 mol KHP = 0.0223 x 204'22 = 4.567 g :. Mass of the KHP sample = 4.5678. ☺ volume of Her solution (U1] = 28.75m2 Strength of Hel solution (sr) = -2055 M Volume of NaOH solution (V2) = ?? 46.93 mL Strength of NaOH solutim (52) = ? Now Viso = 12.52 ar, 39 = 28.75 mL X 0.2055 M 46.93 mL = 0.1258M .. The molarity of NaOH solution = 0.1258 M gf acid was H3 PO4, then also the molarity of Nach solutim will be 0.1258 M . H3PO4 + NQOH -> Na H2 PQq +420 W, Hz Plq + 2NqOH → Na2HPO4 +2tt20 Stoichiometric ratto of NaOH V H3PO4 is eitherli:)

© Volume of mono protic acid solution (VO) = 25 ml Molar concentration of acid solution (31) = ? Molar concentration of NaOH Solution (S2] = 0.2269 m Volume of Naot required for this tritralim (uz) = (3884 – 3.96) - 34.88 ML Now, Viso = V262 or so = 34.88 ML X 0.226.9 M . 25mL e trdott 50.3165 ^ . Molar concentration of the acid solution = 0.3165 M

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