## pH Reactions

1. A solution is prepared by mixing 50 mL of 0.1 M NH3 with 50 mL of 0.1 M NH4Cl.
1. Calculate the pH of this solution.
2. 10 mL of 0.1 M HCl is now added to this solution. Write an equation for the reaction that occurs and then calculate the pH of the solution after the HCl has been added.
3. Calculate the pH of a 0.1 M HCl solution.
2. 5.9 g of trimethyl amine [ (CH3)3N ] is added to enough water to make 1.0 L of solution. 50.0 mL of this solution is placed in an Erlenmeyer flask and is then titrated with 0.100 M HCl.
1. Calculate the pH of the solution in the Erlenmeyer flask before the titration is started.
2. Calculate the pH of the solution at the midpoint of the titration.
3. Calculate the pH of the solution at the equivalence point.
4. What indicator would you choose for the titration?
3. Carefully explain why a solution of aluminum nitrate is acidic. Be sure to use equations.
4. Complete the following equations and tell whether K>1 or K<1 or K=1.
1. BaCl2 + Na2CO3
2. CaCl2 + Fe(NO3)2
3. CH3COOH + SO4-2
4. H2SO3 + NH3
5. H2O + H3O+
6. ZnCO3 + Cd(NO3)2
5. Show how the hydrogen carbonate ion can act as both an acid and a base in water by writing appropriate equations using full electron-dot formulas.
6. Consider ortho-fluoro aniline (o-FC6H4NH2).
1. Give an electron-dot formula for this compound and indicate with an arrow which atoms can accept a proton. Circle the atom that actually does accept a proton from water.
2. Determine whether o-FC6H4NH2 is a stronger or weaker base than aniline itself (C6H5NH2) and explain why this is the case.
3. Calculate the pH of a 0.1 M solution of o-FC6H4NH2.
4. Draw the structural formula of the conjugate acid of o-FC6H4NH2.
5. Calculate the pH of a 0.010 M solution of the conjugate acid of o-FC6H4NH2.
7. Determine whether each of the following 1 M solutions is acidic, basic, or neutral.
1. NaHS
2. NaBr
3. NH4Ac (remember Ac = acetate)
4. KNO2
5. KHSO3
6. NaH2PO4
8. 6.00 g acetic acid and 10.00 g sodium acetate are dissolved in enough water to make 1 L of solution.
1. What is the pH of the solution?
2. If 5 mL of 0.1 M HCl are added to the solution, what is the new pH?
3. If instead 5 mL of 1.0 M KOH are added to the original solution, what is the new pH?
9. Calculate the pH at the beginning, at the midpoint, and at the equaivalence point for the titration also choose an indicator:
1. of 50 mL of 0.1M HCl with 0.1 M NaOH
2. of 50 mL of 0.1 M CF3COOH with 0.1 M NaOH
3. 50 mL of 0.1 M triethylamine with 0.1 M HCl
10. Complete the equation for each of the following reactions and determine the equilibrium constant (that is, give a numerical value) for each reaction:
1. SO3-2 + H2O →
2. NH3 + H3O+