In a hypothetical experiment, you must make a buffer that will hold its pH near pH 7.1. Which of the following equilibrium systems is most likely to be used when creating this buffer and why? (1) (H3)(PO4)(aq)+H2O(l)⟷(H2)(PO4)−(aq)+(H3)O+(aq) pKa1 = 2.148 (2) (H2)(PO4)−(aq)+H2O(l)⟷(H)(PO4)2−(aq)+(H3)O+(aq) pKa2 = 7.198 (3) (H)(PO4)2−(aq)+H2O(l)⟷(PO4)3−(aq)+(H3)O+(aq) pKa3 = 12.35

Identify the buffer system(s) - the conjugate acid-base pair(s)- present in a solution that contains equal molar amounts of the following:      ???3(??????????)      NaOH(sodiumhydroxide)      H3PO4(phosphoricacid)      NaH2PO4(sodiumdihydrogenphosphate)  Group of answer choices HNO3 (nitric acid) and NaOH (sodium hydroxide) HNO3 (nitric acid) and H3PO4 (phosphoric acid) NaOH (sodium hydroxide) and NaH2PO4 (sodium dihyrdogen phosphate) NaH2PO4 (sodium dihyrdogen phosphate) and NaOH (sodium hydroxide) H3PO4 (phosphoric acid) and NaH2PO4 (sodium dihyrdogen phosphate) HNO3 (nitric acid) and NaH2PO4 (sodium dihyrdogen phosphate)

Calculate the pH for the complete titration of 100.0 mL of 0.122 M hydrazine, H2NNH2, with 0.200 M nitric acid.  The Kb for hydrazine is 3.00x10-6. H2NNH2(aq) +HNO3(aq) ⟶ [H2NNH3]+1(aq) + NO3-1(aq)

The Ka of lactic acid is 1.38 x 10^-4

2. A solution contains 250 mL of 0.25M benzoic acid (HBen) and 0.20M sodium benzoate (NaBen). What is the pH of the solution after 25.0 mL of 0.10M HCI have been added? (Ka (HBen) = 6.5 x 10-5) (A) 4.19 (B) 4.107.9 (C) 4.28 c (D) 4.05

Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer solution with an optimum pH of 3.2–3.5 a - NaNO 2 / HNO 2 (K a = 4.5 × 10 –4) b - NaOCl / HOCl (K a = 3.2 × 10 –8) c - NaCl / HCl d - NH 3 / NH 4Cl (K a = 5.6 × 10 –10) e - CH 3COO 2Na / CH 3COOH (K a = 1.8 × 10 –5)

A patient presents to the emergency department in a very critical condition. The patient’s blood was tested and the concentration of carbonic acid (H2CO3) was found to be 4.0×10-4 M and bicarbonate ion (HCO3-) 3.062×10-3 M. Ka = 4.3 × 10-7 H2CO3(aq)  ⇌  HCO3-(aq) + H+(aq) Show all calculations including equation(s) used. a. Calculate the pH of the patients’ blood. b. Based on your answer would you say the patient suffered from Acidosis or Alkalosis

B represents an acid-base indicator and behaves like a base. Its dissociation equilibrium in an aqueous solution can be written as: B(ac) + H2O(l) <-> +BH(ac) + OH(ac) If B (ac) is yellow +BH is red. Using Le Châtelier's principle, predict the color of the indicator by adding a few drops of the indicator to an aqueous solution of HCl and an aqueous solution of NaOH. Write the corresponding chemical reactions.

The pH of blood plasma is 7.40. Assuming that the principal buffer system in blood is HCO, /H2CO3, A) determine the ratio [HCO,]/[H2CO3] in blood plasma. The ionization con- stant of carbonic acid is K.(H2CO3) = 4.3 x 10-7. B) Based on your result in part (A), how many moles of H2CO3 (assuming that they occupy no volume) would need to be added to 300.0 mL of an aqueous solution that is 0.250 mol L- in NaHCO3 to make a buffer solution of the same pH as blood plasma? To solve the problem you may assume that the solutions behave as ideal dilute solutions (solute-type activity coefficients equal to unity).

Describe how you would prepare a H2PO4- /HPO42- buffer solution with a pH of 7.40 from the sodium salts of both the H2PO4- and HPO42- ions. H2PO4-(aq) +H2O(l) <--> HPO42-(aq) + H3O+(aq)Ka = 6.2x10-8