Problem 171
Consider a \(0.67-M\) solution of \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}\left(K_{\mathrm{b}}=5.6 \times 10^{-4}\right)\) a. Which of the following are major species in the solution? i. \(C_{2} \mathrm{H}_{5} \mathrm{NH}_{2}\) ii. \(\mathrm{H}^{+}\) ii.. \(\mathrm{OH}^{-}\) iv. \(\mathrm{H}_{2} \mathrm{O}\) v. \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{3}+\) b. Calculate the \(\mathrm{pH}\) of this solution.
Problem 172
Rank the following 0.10\(M\) solutions in order of increasing \(\mathrm{pH.}\) a. \(\mathrm{NH}_{3}\) b. KOH c. \(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\) d. \(\mathrm{KCl}\) e. HCl
Problem 174
Calculate the pH of the following solutions: a. 1.2\(M \mathrm{CaBr}_{2}\) b. 0.84\(M \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3} \mathrm{NO}_{3}\left(K_{\mathrm{b}} \text { for } \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}=3.8 \times 10^{-10}\right)\) c. 0.57\(M \mathrm{KC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}\left(K_{\mathrm{a}} \text { for } \mathrm{HC}_{7} \mathrm{H}_{5} \mathrm{O}_{2}=6.4 \times 10^{-5}\right)\)
Problem 176
The pH of \(1.0 \times 10^{-8} M\) hydrochloric acid is not \(8.00 .\) The correct pH can be calculated by considering the relationship between the molarities of the three principal ions in the solution \(\left(\mathrm{H}^{+}, \mathrm{Cl}^{-}, \text { and } \mathrm{OH}^{-}\right) .\) These molarities can be calculated from algebraic equations that can be derived from the considerations given below. a. The solution is electrically neutral. b. The hydrochloric acid can be assumed to be 100\(\%\) ionized. c. The product of the molarities of the hydronium ions and the hydroxide ions must equal \(K_{w}\) Calculate the pH of a \(1.0 \times 10^{-8}-M\) HCl solution.
Problem 178
Calculate \(\left[\mathrm{OH}^{-}\right]\) in a \(3.0 \times 10^{-7}-\) M solution of \(\mathrm{Ca}(\mathrm{OH})_{2}\)
Problem 180
Making use of the assumptions we ordinarily make in calculating the \(\mathrm{pH}\) of an aqueous solution of a weak acid, calculate the pH of a \(1.0 \times 10^{-6}-\mathrm{M}\) solution of hypobromous acid \(\left(\mathrm{HBrO}, K_{\mathrm{a}}=2 \times 10^{-9}\right) .\) What is wrong with your answer? Why is it wrong? Without trying to solve the problem, explain what has to be included to solve the problem correctly.
Problem 182
Determine the pH of a \(0.50-M\) solution of \(\mathrm{NH}_{4} \mathrm{OCl.}\) . See Exercise \(181 .\) )
Problem 184
What mass of \(\mathrm{NaOH}(s)\) must be added to 1.0 \(\mathrm{L}\) of 0.050 \(\mathrm{M}\) \(\mathrm{NH}_{3}\) to ensure that the percent ionization of \(\mathrm{NH}_{3}\) is no greater than 0.0010\(\% ?\) Assume no volume change on addition of \(\mathrm{NaOH} .\)
Problem 185
Consider 1000 . mL of a \(1.00 \times 10^{-4}-M\) solution of a certain acid HA that has a \(K_{\text { a value equal to } 1.00 \times 10^{-4} . \text { How much }}\) water was added or removed (by evaporation) so that a solution remains in which 25.0\(\%\) of \(\mathrm{HA}\) is dissociated at equilibrium? Assume that HA is nonvolatile.
Problem 186
Calculate the mass of sodium hydroxide that must be added to 1.00 \(\mathrm{L}\) of \(1.00-M \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\) to double the pH of the solution (assume that the added NaOH does not change the volume of the solution).
