I saw this question:
Find the concentration of proton after adding a acid to NaOH
(before it was put on hold) where I believe the chosen answer is incorrect, because the chosen answer assumes that each molecule of $\pu{\ce{H2SO4}}$ is donating both protons ("each $\pu {\ce {[H2SO4]} mol}$ gives $\pu {2\ce {[H3O+]} mol}$s"). But in a solution of sulfuric acid, all molecules donate the first proton, but only some of the molecules donate the second proton.

So, first things first, am I at least correct that the chosen answer was wrong? (Confusingly, the OP also supplied the given "correct answer" of 0.50 mol that came with the problem, which matched the chosen answer, i.e. the one I think is wrong.)

So I was pretty sure the answer was incorrect. However, in order to edit the answer and replace it with the correct answer, I would have to make an ICE chart and solve a quadratic equation using the dissociation constant for the second proton, and I didn't have time on the fly to do that. And you're not supposed to leave a second answer responding to another answer. And I didn't have enough reputation to leave a comment. So, I did nothing.

What should a user do in that situation? If you believe that an answer is probably incorrect, even if you don't have time to calculate the right answer, you are still contributing positively if you mark the incorrect answer as incorrect. Is there a way to do that, if you can't leave a comment?

(Note that the question was put on hold as a "Homework question" -- which I think is clearly right -- however, that's a different issue. As long as the question is up on the site, and if the chosen answer is incorrect, it has the potential to mislead people unless the incorrect answer is marked as such.)

  • $\begingroup$ I think you should tie a knot to remember to come back, calculate and comment the correct results so the answerer edits their reply. That is, if the only thing wrong with the answer is calculations and you can't simply add another, correct answer addressing mainly the question. $\endgroup$
    – M.A.R.
    Commented May 29, 2018 at 0:24
  • $\begingroup$ @M.A.R.ಠ_ಠ well what about questions where I only know enough to know that the accepted answer is incorrect, but I don't know enough to calculate the correct answer? I would still be contributing positively if I just have a way to mark the accepted answer as incorrect. If there's no way to do it in the existing system then I can submit it on meta SE as a feature request. $\endgroup$
    – Bennett
    Commented May 30, 2018 at 21:27
  • $\begingroup$ Wouldn't commenting work in that case? $\endgroup$
    – M.A.R.
    Commented May 30, 2018 at 21:30
  • $\begingroup$ @M.A.R.ಠ_ಠ I would have, but like I said in the post I don't have enough reputation to leave a comment. (And this question, which to me sounded reasonable, got voted down to -1 which didn't help :-P ) $\endgroup$
    – Bennett
    Commented May 30, 2018 at 21:32

1 Answer 1


If an answer is wrong or misleading, downvote it.

If you want to downvote an answer as being wrong, please be sure that it actually is wrong—sometimes, intuition may lead us astray. However, it is not required to do a full calculation; sometimes a rough estimate is sufficient (as in the example question).

If you have time to come back and provide the correct answer, by all means do so.

If the question has since been closed—tough luck, no answer. Unless it was wrongfully closed, in which case comment and if applicable edit so it may be reopened (or drop a reopen vote if enough rep).

I reread the question after posting this and noticed that at the time you did not have the reputation for commenting or downvoting. In that case, the only thing you can do is wait. Somebody else will find it and hopefully notice it is wrong. If you want to speed up the process, you can try the chat.


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