2. (a) For the neutralization reaction: (i) HB + OH B + HO Calculate the...

 

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2. (a) For the neutralization reaction: (i) HB + OH → B + H₂O Calculate the value of the equilibrium constant for 99.99% conversion of HB into B at the equivalence point, assuming that the analyte content is 5.000 mmol and the total volume at the equivalence point is 100.00 mL. (6 marks) (ii) Would a larger value of the equilibrium constant be expected for a higher degree of completion at the equivalence point? Explain why. (2 marks) (iii) What factors affect end-point sharpness in an acid-base titration? (2 marks) (b) In an experiment, 20.00 mL of a diprotic acid, H₂A, is titrated with 0.100 M NaOH. The resulting titration curve is shown below. Hd 14 12 10 8 6 4 2 0 4 0 20 30 Volume of 0.100 M NaOH (mL) (i) Identify points A, B, C and D in the course of the titration. 10 40 (ii) Estimate the concentration of H₂A from the titration result. (iv) Estimate K and K₂ for this acid. 50 (4 marks) (1 mark) (iii) Express the pH at points A, B, and C in terms of K₁ and K₂, the stepwise acid dissociation constants of H₂A. Explain your answers briefly. (3 marks) (2 marks) 2. (a) For the neutralization reaction: (i) HB + OH → B + H₂O Calculate the value of the equilibrium constant for 99.99% conversion of HB into B at the equivalence point, assuming that the analyte content is 5.000 mmol and the total volume at the equivalence point is 100.00 mL. (6 marks) (ii) Would a larger value of the equilibrium constant be expected for a higher degree of completion at the equivalence point? Explain why. (2 marks) (iii) What factors affect end-point sharpness in an acid-base titration? (2 marks) (b) In an experiment, 20.00 mL of a diprotic acid, H₂A, is titrated with 0.100 M NaOH. The resulting titration curve is shown below. Hd 14 12 10 8 6 4 2 0 4 0 20 30 Volume of 0.100 M NaOH (mL) (i) Identify points A, B, C and D in the course of the titration. 10 40 (ii) Estimate the concentration of H₂A from the titration result. (iv) Estimate K and K₂ for this acid. 50 (4 marks) (1 mark) (iii) Express the pH at points A, B, and C in terms of K₁ and K₂, the stepwise acid dissociation constants of H₂A. Explain your answers briefly. (3 marks) (2 marks)