Chapter 17

A 0.25-mol sample of a weak acid with an unknown pKa is combined with 10.0 mL of 3.00 M KOH, and the resulting solution is diluted to 1.500 L. The measured pH of the solution is 3.85. What is the pKa of the weak acid?

The Kb of hydroxylamine, NH2OH, is 1.10 * 10-8. A buffer solution is prepared by mixing 100.0 mL of a 0.36 M hydroxylamine solution with 50.0 mL of a 0.26 M HCl solution. Determine the pH of the resulting solution.

A 0.867-g sample of an unknown acid requires 32.2 mL of a 0.182 M barium hydroxide solution for neutralization. Assuming the acid is diprotic, calculate the molar mass of the acid.

A 25.0-mL volume of a sodium hydroxide solution requires 19.6mL of a 0.189 M hydrochloric acid for neutralization. A 10.0-mL volume of a phosphoric acid solution requires 34.9 mL of the sodium hydroxide solution for complete neutralization. Calculate the concentration of the phosphoric acid solution.

Derive an equation similar to the Henderson-Hasselbalch equation for a buffer composed of a weak base and its conjugate acid. Instead of relating pH to pKa and the relative concentrations of an acid and its conjugate base (as the Henderson-Hasselbalch equation does), the equation should relate pOH to pKb and the relative concentrations of a base and its conjugate acid.

What volume of 0.100 M sodium carbonate solution is required to precipitate 99% of the Mg from 1.00 L of 0.100 M magnesium nitrate solution?

Find the pH of a solution prepared from 1.0 L of a 0.10 M solution of Ba(OH)2 and excess Zn(OH)2(s). The Ksp of Zn(OH)2 is 3 * 10-15, and the Kf of Zn(OH)4 2- is 2 * 10-15.

A buffer contains 0.10 mol of a weak acid and 0.20 mol of its conjugate base in 1.0 L of solution. Determine whether or not each addition exceeds the capacity of the buffer. a. adding 0.020 mol of NaOH b. adding 0.020 mol of HCl c. adding 0.10 mol of NaOH d. adding 0.010 mol of HCl

Equal volumes of two monoprotic acid solutions (A and B) are titrated with identical NaOH solutions. The volume needed to reach the equivalence point for solution A is twice the volume required to reach the equivalence point for solution B, and the pH at the equivalence point of solution A is higher than the pH at the equivalence point for solution B. Which statement is true? a. The acid in solution A is more concentrated than in solution B and is also a stronger acid than that in solution B. b. The acid in solution A is less concentrated than in solution B and is also a weaker acid than that in solution B. c. The acid in solution A is more concentrated than in solution B and is also a weaker acid than that in solution B. d. The acid in solution A is less concentrated than in solution B and is also a stronger acid than that in solution B.

With group members acting as atoms or ions, act out the reaction that occurs when HCl is added to a buffer solution composed of HC2H3O2 and NaC2H3O2. Write out a script for a narrator that describes the processes that occur, including how the buffer keeps the pH approximately the same even though a strong acid is added.