Logo
Home Study Material Contact Search
AI Chat FREE
  1. sciences
  2. chemistry
  3. 1) pyridine is a weak base that is used in the man

1) Pyridine is a weak base that is used in the manufacture of pesticides and plastic...

Free

60.1K

Verified Solution

Question

Chemistry

1) Pyridine is a weak base that is used in the manufacture ofpesticides and plastic resins. It is also a component of cigarettesmoke. Pyridine ionizes in water as follows: C5H5N+H2O⇌C5H5NH++OH−The pKb of pyridine is 8.75. What is the pH of a 0.310 M solutionof pyridine? Express the pH numerically to two decimal places

2)Benzoic acid is a weak acid that has antimicrobial properties.Its sodium salt, sodium benzoate, is a preservative found in foods,medications, and personal hygiene products. Benzoic acid ionizes inwater: C6H5COOH⇌C6H5COO−+H+ The pKa of this reaction is 4.2. In a0.61 M solution of benzoic acid, what percentage of the moleculesare ionized? Express your answer to two significant figures andinclude the appropriate units.

Answer & Explanation Solved by verified expert
3.7 Ratings (568 Votes)

Kb of pyridine = 10^-pKb = 1.78 x 10^-9

C5H5N + H2O <--------------------> C5H5NH+ + OH−

0.310                                                   0               0

0.310 - x                                              x               x

Kb = x^2 / 0.310 - x

1.78 x 10^-9 = x^2 / 0.310 - x

x = 2.35 x 10^-5

[OH-] = 2.35 x 10^-5 M

pOH = -log[OH-] = -log (2.35 x 10^-5 ) = 4.63

pH = 9.37

2)

Ka = 6.31 x 10^-5

C = 0.61

[H+] = sqrt (Ka x C)

        = sqrt (6.31 x 10^-5 x 0.61)

         = 6.2 x 10^-3 M

% ionized = ([H+] / C ) x 100

                = (6.2 x 10^-3 / 0.61 ) x 100

                = 1.0 %
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: Zin AI - Your personal assistant for all your inquiries!
Become a Member

Other questions asked by students

Q

when some monosaccharaides are in solution: what structural modification occurs? considering the structural modification above, what type...

Biology
Q

This was the only information given in the question In 2012, the Detroit Tigers and the...

Basic Math
Q

hello 5. In 1983 the Bell Telephone System was broken up resulting in the creation of seven...

Finance
Q

12. Indicate below whether the installment sale method of accounting can apply to each of these...

Accounting
Q

What is the most common infectious disease worldwide O HIV O hepatitis C O tuberculosis

Biology
Q

127 A 10m long wire of resistance 15 ohm is connected in series with a...

Physics
Q

Solve the equation where x is any real number cos2x 1 2

Geometry
Q

42 Evaluate sin 54 cos 9 cos 54 sin 9 What is the second step...

Calculus
Q

expenses erept interest. III (Clik tive ioon laview the...

Accounting
Q

Section V A company expects its three departments to...

Accounting
Q

INSTRUCTIONS: Indicate the placement on financial statements of the items listed below by inserting the...

Accounting
Q

Douglas Company's beginning inventory and purchases during the fiscal year ended December 31, 20, were...

Accounting