A 25.0 mL sample of 0.125 molL−1 pyridine (Kb=1.7×10−9) is titrated with 0.100 molL−1HCl. Calculate the pH...

Free

50.1K

Verified Solution

Question

Chemistry

A 25.0 mL sample of 0.125 molL−1 pyridine (Kb=1.7×10−9) istitrated with 0.100 molL−1HCl.

Calculate the pH at one-half equivalence point.

Calculate the pH at 40 mL of added acid.

Calculate the pH at 50 mL of added acid.

Answer & Explanation Solved by verified expert
4.0 Ratings (610 Votes)

1)

millimoles of pyridine = 25.0 x 0.125 = 3.125

concentration of HCl = 0.100 M

Kb = 1.7 x 10^-9

pKb = 8.77

a) at half - equivalence point :

pOH = pKb

pOH = 8.77

pH = 5.23

b) at 40 mL of added acid.

mmoles of HCl = 40 x 0.100 = 4

C5H5N   +   HCl   ----------------> C5H5NH+

3.125          4                                   0

     0           0.875                            3.125

here strong acid remains.

[H+] = 0.875 / 40 + 25 = 0.01346 M

pH = -log (0.01346)

pH = 1.87

c) 50 mL of added acid.

pH = 1.60


Get Answers to Unlimited Questions

Join us to gain access to millions of questions and expert answers. Enjoy exclusive benefits tailored just for you!

Membership Benefits:
  • Unlimited Question Access with detailed Answers
  • Zin AI - 3 Million Words
  • 10 Dall-E 3 Images
  • 20 Plot Generations
  • Conversation with Dialogue Memory
  • No Ads, Ever!
  • Access to Our Best AI Platform: Flex AI - Your personal assistant for all your inquiries!
Become a Member

Other questions asked by students