acid base - Ans.fyi 參考答案

acid base

2008-03-02 8:54 am

(1)What ions and/or molecules are present in relatively large proportions in a solution of a weak acid, HF (aq)? select all correct answers.why
HF,F-, HF+,F+, F2+, H2-, F2-,H,F
(2)What ions and/or molecules are present in relatively large proportions in a solution of a strong base NaOH (aq)? select all correct answers. why
NaOH,Na2+,OH2-,OH-,NaO+,OH+,Na,Na+,OH

回答 (1)

Uncle Michael

2008-03-02 9:25 am

✔ 最佳答案

(1) The answers are HF, H+ and F-.
HF(aq) is a weak acid. It can be partly ionized in water to give H+(aq) and F-(aq).
HF(aq) = H+(aq) + F-(aq) [reversible]
All other listed species are unstable, and even cannot exist.
(In AL syllabus, there are also H2F+ and HF2- in the solution.)

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(2) The answers are Na+ and OH-.
NaOH(s) contains Na+ and OH- ions, and the ions are well arranged. When the solid is dissolved in water, it is completely dissociated to give mobile Na+(aq) and OH-(aq).
NaOH does not exist in the solution, because it has been dissociated in water.
All other listed species are unstable, and even cannot exist.

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