Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

A ) Using the titration curve shown below, at what volume of acid added will pH

ID: 896819 • Letter: A

Question

A)

Using the titration curve shown below, at what volume of acid added will pH = pKa?

0 mL

25 mL

50 mL

100 mL

1 points   

B)

Using the titration curve shown below, at what volume of acid added will the pH depend only on the amount of excess strong acid added?

0 mL

50 mL

100 mL

120 mL

1 points   

C)

Consider the following three titrations:

1- 100.0 mL of 0.100 M HCl titrated with 0.100 M NaOH

2- 100.0 mL of 0.100 M NH3 (Kb = 1.8x10-5) titrated with 0.100 M HCl

3- 100.0 mL of 0.100 M HOCl (Ka = 2.9x10-8) titrated with 0.100 M NaOH

Which titration will have the lowest pH at the equivalence point?

1

2

3

They all have the same pH at the equivalence point.

2 points   

D)

30.0 ml of an HCl solution of unknown molarity was titrated with .200 M NaOH. Phenolphthalien was used as the indicator. The titrated solution turned a very pale pink after 20.3 mL of NaOH was added. What was the initial molarity of the HCl?

1 points   

F)

A solution was tested with several indicators to estimate its pH. When added to the solution, bromcresol green turned blue, phenolphthalien turned colorless and bromthymol blue turned green. What is the approximate pH of the solution? (Refer to the table of indicators in your text book.)

8

7

6

5

a.

0 mL

b.

25 mL

c.

50 mL

d.

100 mL

Explanation / Answer

A. Cannot see the titration curve, but usinh H-H equation,

pH = pKa + log [base/acid]

So, pH = pKa when [base]=[acid] which is at half equivalence.