Reference no: EM132554162

In a 0.500 M solution of HNO2 (Ka = 4.0 x 10-4 ), the equilibrium that contributes most to the concentration of H3O+ is the following:

HNO2(aq) + H2O(l) ? H3O+ (aq) + NO2 - (aq)

At the same time, the underlying equilibrium between water molecules still holds:

H2O(l) + H2O(l) ? H3O+ (aq) + OH- (aq) Kw = 1.0 x 10-14

1. What effect does the dominant equilibrium have on the amount of H3O+ produced by the autoionization of water? (Does it shift it in any direction, and if so, which direction, and why?) What effect does it have on the amount of OH- produced by the auto-ionization of water?

2. Please write the chemical formula of both the conjugate base and conjugate acid that could be formed by the amphoteric molecule H2Y.

3. Use the Henderson-Hasselbach equation to calculate the pH of a buffer system prepared by dissolving 0.300 g of potassium benzoate (KC6H5COO, 160.21 g/mol) with 0.300 g of benzoic acid (C6H5COOH, 122.12 g/mol) in enough water to make 50.0 mL of solution. The pKa of benzoic acid is 4.202.

4. What is the pH of a 0.305 M HCl solution?

5. Calculate the [OH - ] in a solution that has a pH of 3.32.

6. When Na2S is added to water, the sulfide ion can react with water as a weak base. Please write out the balanced chemical equilibrium reaction that shows this weak base behavior.