# Is it correct to consider dissolving HCl gas in water as oxidation –reduction process?

References define oxidation –reduction process as change in oxidation number ,Accordingly it is not appropriate to describe the mentioned process as oxidation –reduction because there is no change in oxidation number of atoms and it is not a chemical reaction .

But the teacher consider it as oxidation –reduction reaction because HCl gas ionize in water . Iam confused , so any idea will greatly help.

• No. The oxidation state of neither H nor Cl changes so it is not a redox reaction. Dissolving NaCl isn't a redox reaction either. – MaxW Mar 9 '17 at 19:53
• Teacher consider H as an atom in HCl molecule but separate as an ion in water and Cl atom gained electron from H to form negative ion ,accordingly H loose to Cl – Adnan AL-Amleh Mar 9 '17 at 20:00
• Do you mean in your above comment Dissolving HCl or Nacl isn't a redox reaction ? – Adnan AL-Amleh Mar 9 '17 at 20:07
• :( neither are redox reactions. – MaxW Mar 9 '17 at 20:13
• You need a different teacher! The Chlorine in HCl is already in the -1 oxidation state, dissolving it in water does not change this. – Waylander Mar 9 '17 at 20:16

## 1 Answer

Given the dissolution of $\ce{HCl}$ gas in water:

$$\ce{HCl(g) + H2O(l) <-->H3O+(aq) +Cl-(aq)}$$

The oxidation state of all hydrogen atoms is +1 and that of all chlorine atoms is -1. Thus, nothing has been oxidized or reduced, and no redox reaction has taken place.

• just to make sure ,Can I consider ionization of acetic acid in water as oxidation - reduction reaction ? – Adnan AL-Amleh Mar 10 '17 at 6:04
• For the same reason, no, you would not. Neither acetic acid nor water are being reduced or oxidized in that process. – airhuff Mar 10 '17 at 6:07