Part A.
1. Consider the following reaction at a certain temperature:

SO2(g) + NO2(g) ? SO3(g) + NO(g)

Calculate the equilibrium constant for the reaction at that temperature of at equilibrium the partial pressures are PSO2 = PNO2 = 0.50 atm, and PNO = PSO3 = 2.0 atm.

2. Assume that at equilibrium one has the partial pressures of the given species in Part 1. Then suppose enough SO2 and NO2 are added to raise both their partial pressures temporarily at 2.00. What are the partial pressures of all the species when equilibrium is re-established?

Part B.
A 1.00 M solution of NaHSO4 is found to have a pH of 1.022. What is the Ka of this acid?

Part C.
Consider the titration of 50.0 mL of 0.15 M benzoic acid (C6H5COOH, Ka = 6.3 x10-5) with 0.20 M NaOH. (You can use HBen for benzoic acid)

1. What is the pH when 30.0 mL of base is added?

2. How many mL of NaOH are required to reach the equivalence point?

3. What is the pH at the equivalence point?

Part D.
Ksp for PbCrO4 at 25oC is 2.0 x 10-14. A sample of 1.000 mg of PbCrO4 is added to 1.0 L of water at this temperature.

1. How many milligrams of PbCrO4 dissolves?

2. How many milligrams of PbCrO4 remains undissolved?

3. If 1.000 mg of PbCrO4 are added to 1.00 L to 0.100 M Na2CrO4 at 25oC, how many mg of the PbCrO4 dissolves?