[o1ocups]

Question: For C7H5O2-, write an equation that shows how the anion acts as a base.
My answer: C7H5O2-(aq)+H2O(l) C7H6O2(aq)+OH-(aq) ...WRONG!!

Should I write C7H6O2(aq)+H2O(l) C7H5O2-(aq)+H3O+, then?
(to show that C7H5O2- is the conjugate base of the acid...?)
But why doesn't my first equation work?

[Borek]

What base definitions do you know?

I suppose you are expected to use Brønsted-Lowry definition.

[o1ocups]

What base definitions do you know?

I suppose you are expected to use Brønsted-Lowry definition.

I am most familiar with the Brønsted-Lowry definition, but Arrhenius and Lewis definitions are also in the textbook (and taught in class). But how does it matter? How would my response change based on the difference in the defition? 

[Borek]

It doesn't depend on the definition, just read BL definition and see how can you directly apply it to the question.

[nj_bartel]

That answer looks right to me, what am I missing?  Looks like a simple P.T. from water to the anion.

[o1ocups]

That answer looks right to me, what am I missing?  Looks like a simple P.T. from water to the anion.

You mean my first answer? I know right?!! Didn't I already use the Brønsted-Lowry definition that bases are proton acceptors? Well, C7H5O2- accepted a proton from water. That should prove that it's a base, shouldn't it? Maybe the question is just poorly worded. 

[nj_bartel]

Yes, how you answered it is how I would have answered it, and the question seems pretty transparent to me.  However, Borek is definitely more knowledgeable than me as far as this, so I'd suggest you wait and see what he has to say.

[Hosanna]

Try writing "C7H6O2(aq)" as "HC7H5O2(aq)."

[o1ocups]

Try writing "C7H6O2(aq)" as "HC7H5O2(aq)."

But isn't that the same thing?  the system is usually pretty fair.

[Borek]

I would accept the answer.

However, my bet is that whoever asked the question wanted you to use H₃O⁺ (or even just H⁺) on the reactants side.

[Hosanna]

Try writing "C7H6O2(aq)" as "HC7H5O2(aq)."

But isn't that the same thing?  the system is usually pretty fair.

If this is MasteringChemistry, rewriting it this way should solve the issue.

[o1ocups]

Well, if you say so!  (It is MasteringChemistry)




And it worked!

Thanks everyone.

[nj_bartel]

masteringchemistry sucks.

[Borek]

Looks like. You should be concentrating on chemistry, not on tricks necessary to make the system understand the answer. That's plain stupid.

[o1ocups]

I completely agree with both of you that masteringchemistry SUCKS