RedOx Reactions & Phase Changes

[somasimple]

Hi,

In electro-chemical cells (galvanic, concentration, etc) or more generally when some RedOx reactions occur in solutes, is there always a phase change?
I mean is there always a change in the state of matter from liquid to solid or gas?

 

[Borek]

No.

Pt|Fe²⁺(aq),Fe³⁺(aq)||Ce⁴⁺(aq),Ce³⁺(aq)|Pt

(I haven't used cell notation in ages, chances are I did some mistake, but you should get the idea).

 

[somasimple]

May we say that the use of Platinum is certainly a special case?
Can I rephrase my sentence like that?

In electro-chemical cells (galvanic, concentration, etc) or more generally when some RedOx reactions occur in solutes containing the ionic form of the metal that made the electrode, is there always a phase change?
I mean is there always a change in the state of matter from liquid to solid or gas?

 

[Borek]

Well, if you specifically ask for a reaction in which the reactant and product are in different phases then the phase change seems inevitable, doesn't it?

 

[somasimple]

You're The Man!

 

[James Demers]

There are plenty of redox reactions that occur entirely in solution, particularly among transition metal ions. Oxyhalide ions like bromate and hyopchlorite also effect oxidations without a phase change. A butane lighter is an example of gas-phase redox chemistry.

Batteries are a special case, since you almost always have a metallic anode.