Question

Problem 16.63

Calculate the percent ionization of hydrazoic acid (HN3) in solutions of each of the following concentrations (Ka is given in Appendix D in the textbook).

Part A

0.388 M .

Express your answer using two significant figures.

  %  

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Part B

0.117 M .

Express your answer using two significant figures.

  %  

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Part C

3.61×10⁻² M .

Express your answer using two significant figures.

  %  

Answer 1

Ka = Cα²    α= percent ionization

α = (Ka/C)^1/2

Ka of hydrazoic acid (HN3) = 1.9 x10^-5

A) C= 0.388 M

α = (Ka/C)^1/2

= ( 1.9 x10^-5 / 0.388)^1/2

= 0.007

= 0.7 %

Therefore,  percent ionization = 0.7 %

B)

C= 0.117 M

α = (Ka/C)^1/2

= ( 1.9 x10^-5 / 0.117)^1/2

= 0.012

= 1.2 %

Therefore,  percent ionization =1.2 %

C)

C= 3.61×10⁻² M

α = (Ka/C)^1/2

= ( 1.9 x10^-5 / 3.61×10⁻² )^1/2

= 0.023

= 2.3 %

Therefore,  percent ionization = 2.3 %