Conjugate bases

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  • #1
Amy-Lee
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Homework Statement


Indicate the conjugate bases of the following:

NH2-
NH2-

Homework Equations





The Attempt at a Solution


This is the only information given. Can I assume that these species react with water? The ionic signs indicate that they are bases, but are they the conjugate bases?
 

Answers and Replies

  • #2
Borek
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What are the definitions of acid and conjuagte base? Can you write acid-base reaction equation involving one of given ions as a reactant and the other as a product?

--
methods
 
  • #3
Amy-Lee
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When species donates a proton, it becomes the conjugate base; when a species gains a proton, it becomes a conjugate acid...

NH2- + H2O -> NH3 + OH-


NH2- becomes a conjugate acid
 
  • #4
PhaseShifter
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When species donates a proton, it becomes the conjugate base;

What does [tex]NH{_2}{^-}[/tex] become when it donates a proton?
 
  • #5
Amy-Lee
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what does [tex]nh{_2}{^-}[/tex] become when it donates a proton?

nh ?
 
  • #6
PhaseShifter
279
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nh ?
Close, but still missing something.

What will the charge be?
 
  • #7
Amy-Lee
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Close, but still missing something.

What will the charge be?

negative
 
  • #8
Amy-Lee
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So is the conjugate base of NH2- N3-?
 
  • #9
Borek
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No, acid and conjugate base must differ by exactly one proton. And PhseShifter didn't ask about positive/negative, but about exact value. You wrote nh (meaning NH) - but what is the exact charge?

--
methods
 
  • #10
Amy-Lee
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No, acid and conjugate base must differ by exactly one proton. And PhseShifter didn't ask about positive/negative, but about exact value. You wrote nh (meaning NH) - but what is the exact charge?

NH-
 
  • #11
Borek
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Oops, sorry, somehow I missed track of hydrogens and charge :blushing:

So is the conjugate base of NH2- N3-?

That was right. I misread it as NH2-, not NH2-.

Still, nh was wrong - should be NH2-. Treat my mistake as a warning why you should never ignore capitalization and charge - it adds to the confusion.

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  • #12
Amy-Lee
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I will, thank you so much for all your help and patience.
 

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