Redox reactions - how do we know two reactants will undergo a redox reaction?

[golden]

For example, with NaBr and F2 (gas) how do we figure out if it reacts or not?
(It does react).

Thanks in advance.

[Martoman]

list ions

Na+ Br- and F2

Look at your table. Line of negative gradient means spontaneous reaction and the highest up on the left will react with the lowest on the right.

So F2 will react with *everything* on the right.

Na+ is on the same side as F2 so no go.

But Br- is on the right side.

So F2 will react with Br-

So now you have F2 + 2e -> 2F-

and 2Br- -> Br2 + 2e-

[golden]

Thanks.

What about MgCl2 and Fe(s)?
Cl2 and Fe have a negative gradient, apparently the two do not react. Or are the answers wrong?

[golden]

Topic: Redox reactions - how do we know if two reactants will undergo a redox reaction?*

[scocliffe09]

Thanks.

What about MgCl2 and Fe(s)?
Cl2 and Fe have a negative gradient, apparently the two do not react. Or are the answers wrong?

In MgCl2 you have Cl-, not Cl2 -that's why they don't react.

[golden]

Thanks.

What about MgCl2 and Fe(s)?
Cl2 and Fe have a negative gradient, apparently the two do not react. Or are the answers wrong?

In MgCl2 you have Cl-, not Cl2 -that's why they don't react.

Thanks.

[masonnnn]

we got taught this whole 'line crossing over' thing of working it out...
"negative gradient" is so much simpler. that's genius. why have i not been using that for 2 years. shit.

and this would mean positive gradient of the...least incline for electrolysis?

[naved_s9994]

Topic: Redox reactions - how do we know if two reactants will undergo a redox reaction?*

Change in oxidation number assigned.

[masonnnn]

and this would mean positive gradient of the...least incline for electrolysis?

? ...would...it?

[golden]

and this would mean positive gradient of the...least incline for electrolysis?

? ...would...it?

We got taught that there would be no reaction if it was a positive gradient. But that's Unit 2.