1) Calculate pH and pOH at 25°C of an aqueous solution of XXXXXXXXXXM KOH. Hint: this is a strong base. (10 points) 2) The pH of the contents of the human stomach can be as low as 1.0 Calculate the...

1) Calculate pH and pOH at 25°C of an aqueous solution of 0.07128 M KOH. Hint: this is a
strong
base. (10 points)

2) The pH of the contents of the human stomach can be as low as 1.0 Calculate the value of [H₃O⁺] and [OH^-] in the stomach when the pH = 1.0. (10 points)

3) The [H₃O⁺] at equilibrium of a 1.00 × 10^-2
M solution of an unknown
weak
acid is 1.62 × 10^-5
M at 25°C. Calculate the value of K_a
for the acid. (10 points)

4) The organic solvent pyridine, C₅H₅N, is a weak base with a strong, irritating odor. Calculate the pH of a 0.300 M aqueous solution of pyridine at 25°C. The K_b
value for pyridine is 1.58 × 10^-9
M. (10 points)

5) Answer the following questions. I am asking for chemical reactions with products and reactants, not mathematical equations for K. (3 points each)

a) Write the K_a
reaction for a solution of chloric acid, HClO₃.

b) Write the K_a
reaction for a solution containing the methylammonium ion, CH₃NH₃
⁺.

c) Write the K_b
reaction for a solution containing the hypobromite ion, OBr^-.

6) Calculate the pH of a buffer solution that is 0.200 M in pyridine (a weak base), C₅H₅N (aq) and 0.250 M in pyridinium chloride, C₅H₅NH⁺Cl^-
(aq). The pyridinium ion, C₅H₅NH⁺, is the conjugate acid of pyridine. The pK_a
value for the pyridinium ion is 5.199 M. (10 points)

7) Suppose that you have 1.00 L of the solution in problem 6 and you add 10.0 mL of 5.00 M HCl to it. What would be the new pH of the solution? (11 points)

8) Clorox™, the common household bleach, is a 6.0% solution of sodium hypochlorite, NaOCl. The 6.00% concentration is equivalent to a 0.806 M solution. Calculate the pH of Clorox™. The K_a
for hypochlorous acid, HClO, (the conjugate acid of hypochlorite) is 0.0115. Note: go ahead and make a simplifying assumption to solve this problem, even though the assumption will not be valid. (10 points)

9) A saturated solution of potassium perchlorate, KClO₄, is 0.0505 M. (In other words, the solubility (x) of KClO₄
is 0.0505 M.) Calculate the value of K_sp
of KClO₄. (10 points)

Calculate the solubility (in molarity, M) of Pb(IO₃)₂
(s) that is also 0.10 M in KIO₃
(aq) at 25°C. The K_sp
value of Pb(IO₃)₂
is 3.7 × 10^-13
M³. The molar mass of Pb(IO₃)₂
is 557.01 g/mol. Hint: this is a
common ion effect
problem. The initial concentrations will not all be 0 M. (10