Conjugate Bases of NH2-: Identifying

[Amy-Lee]

Homework Statement

Indicate the conjugate bases of the following:

NH₂^-
NH^2-

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?

 

[Borek]

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?

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methods

 

[Amy-Lee]

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

 

[PhaseShifter]

When species donates a proton, it becomes the conjugate base;

What does $$NH{_2}{^-}$$ become when it donates a proton?

 

[Amy-Lee]

what does $$nh{_2}{^-}$$ become when it donates a proton?

nh ?

 

[PhaseShifter]

nh ?

Close, but still missing something.

What will the charge be?

 

[Amy-Lee]

Close, but still missing something.

What will the charge be?

negative

 

[Amy-Lee]

So is the conjugate base of NH^2- N^3-?

 

[Borek]

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?

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methods

 

[Amy-Lee]

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^-

 

[Borek]

Oops, sorry, somehow I missed track of hydrogens and charge

So is the conjugate base of NH^2- N^3-?

That was right. I misread it as NH₂^-, not NH^2-.

Still, nh was wrong - should be NH^2-. Treat my mistake as a warning why you should never ignore capitalization and charge - it adds to the confusion.

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[Amy-Lee]

I will, thank you so much for all your help and patience.