Question

Part 1:

Trial	Initial pH	Final pH	Final volume after titration	Initial Buret Reading	Total Volume Titrated
#1	3.34 pH	4.35 pH	47.50 mL	50 mL	2.50 mL
#2	3.39 pH	4.20 pH	47.90 mL	50 mL	2.10 mL
#3	3.39 pH	4.40 pH	47.00 mL	50 mL	3.00 mL

Part 2:

Trial	Initial pH	Final pH	Final volume after titration	Initial Buret Reading	Total Volume Titrated
#1	5.01 pH	5.03 pH	48.00 mL	50 mL	2.00 mL
#2	5.01 pH	5.04 pH	47.00 mL	50 mL	3.00 mL
#3	5.01 pH	5.04 pH	47.50 mL	50 mL	2.50 mL

Part 3:

Trial	Initial pH	Final pH	Final volume after titration	Initial Buret Reading	Total Volume Titrated
#1	5.01 pH	4.99 pH	47.00 mL	50 mL	3.00 mL
#2	5.01 pH	4.98 pH	46.80 mL	50 mL	3.20 mL
#3	5.01 pH	5.00 pH	47.50 mL	50 mL	2.50 mL

1.According to your observations, in Part 2 and Part 3, did your buret values agree with one another? If not, how would you explain the difference?

2. What conclusions can you draw when you compare Part 1 to Part 2? What about when comparing Part 1 to Part 3? Explain your reasoning.

3. Given the following, determine which set(s) correctly represents a buffer system. Explain your reasoning.

1. NaNO₃

HF and KF

HCl and NaOH

HC₂H₃O₂ and NaC₂H₃O₂

4. What is the pH of a solution prepared by dissolving 1.00 g of Ca(OH)₂ in water to make 875 mL of the solution? Show your calculations.

5. Given the following pair, determine which one is more basic. Explain your reasoning.

Photo developer with a pH of 12.0 or a solution of borax with a pH of 9.2

Answer 1

1. in the case of 2 the pH is increasing while that of case 3 pH is decreasing so there is no similarity in titrant used for titrating.

2. pH is increasing in the range of 0.8 to 1.01 in case (1) on the hand only 0.02 to 0.03 in the case of (2) titration. while using a similar amount of titrant. we can conclude that both are titrated with the basic solution strong in 1, and weak basic solution in the 2.

3. HC2H3O2/ KC2H3O2 the pair of buffer solution. The buffer solution is the combination of a weak solution with its salt.

4. Molar mass of Ca(OH)₂ , M= 74.09, Volume of the solution, V = 875 ml and Wt of Ca(OH)₂ , w= 1 gm

Molarity of Solution=(w/M) * 1000/V on putting values we get, 0.0154 Mol/liter. This

is the concentration of Ca(OH)₂, but the concentration of hydroxyl ions is twice that of Ca(OH)_2. that is 0.0308 or 3.08 X 10^-2.

pOH= -log (OH^-)= 1.511

pH= 14- pOH= 14-1.511= 12.39

5. solution of photo developer is more basic than that of borax. higher the pH more basic is the solution.