Answer Happy

I know this quite a bit, but I am begging for help. I really need to pass this class!
Part 1: Write equation for each solution, which is acid and which is base?
part 2: based on definition of a buffer, explain why the samples that behaved as buffers did so, what did they have in the solution that allowed them to act as a buffer? Why did the other solutions not?
Procedure Preparation of sample solutions Sample 1: (Pare Water): Boil 300 mL of deionized wnter in a 400 mL besker to expel the dissolved carbon dioxide. Let it cool to room temperature. The beaker may be placed in cold Water several times for rapid cooling. Sample 2: (0.001M Hydrochloric Acid): Prepare 100 mL of this solution by diluting 1.0 mL of 0.10M hydrochlorie acid solution to 100.0 mL in a volumetric flask whth the boiled deionized water. Homogenize the solution. Sample 3: (0.001 M Sodium Hydroxide): Prepure 100 mL of this solution by diluting 1.0 mL of 0.10 M sodium hydroxide solution to 100.0 mL in a volumetric flask with the boiled deionized water. Homogenize the solution. Sample 4: (Phosphate Combo): Mix 10.0 mL of 0.5M sodium dihydrogen phosphate solution with 10.0ml of 0.5M sodium monohydrogen phosphate solution. Homogenize the solution. Sample 5: (Ammonium Combo): Mix 10.0 mL of 1.0M ammonium hydroxide solution with 10.0nl of 1.0M ammonium chloride solution. Homogenize the solution. pH measarament Determine the pH of each of the five samples prepared above by using pH paper. If both Widde-range and narrow-range pH papers are available, use the procedure given on page 15.1. Record the better value only. Take 9.5 mL of each of the five samples prepared above in separate test tubes. Add one: drop of 1.0M hydrochloric acid to each test tube, stir well to homogenize, and measure the pH of the resulting solution as above. Once sgain, take 9.5 mL of each of the five samples prepared above in separate test tubes. Add one drop of 1.0M sodium hydroxide to each test tube, stir well to homogenize, and measure pH of the resulting solution as before. Question What are the sources of error in this experiment?
A. pH measkrentorr and buyer folenfificafion B. Write two balanced chemical equations to ilhustrate how a hydrogen carbonate ion (also known as bicarbonate ion) could react with either an acid or a base to maintain a constant pH. HCO3​−+H2​O(l)⇌H3​O++CO32−​ (acid)