Which one of the following is equal to the pKa of a weak acid?

[匿名]

2021-01-20 12:41 pm

Which one of the following is equal to the pKa of a weak acid?

Select one:

a. The pKb of its conjugate base

b. The pH of a solution containing equal amounts of the acid and its conjugate base

c. The equilibrium concentration of its conjugate base

d. Its relative molecular mass

回答 (2)

[匿名]

2021-01-20 5:10 pm

✔ 最佳答案

B is the correct answer

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note the wording!

the dissolution is
.. 1 HA <----> H+ + A-

choice B states [A-] = [HA]

from the henderson Hasselbalch equation
.. pH = pKa + log( [A-] / [HA])
.. .. . .= pKa + log( 1 )
.. .. .. = pKa + 0
.. pH = pKa
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For shame Bobby thin. This is a standard analytical technique taught to ALL chemistry undergrad students. Titrate a weak acid with a strong base. Identify the equivalence point. Find the halfway point (where [A-] = [HA]), and the pH = pKa. We've all done the labs. We've all worked through the theories.... All of us except... Bobby thin who stands by his WRONG choice and refuses to correct himself. Ridiculous as that is. Why don't you know this material Bobby thin?

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Bobby

2021-01-20 4:04 pm

a. The pKb of its conjugate base

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