Redox HELP!!! thanks you

[jack_chay]

Ba(NO3)2(aq) + H2SO4(aq) → BaSO4(s) + 2HNO3(aq)

Is barium nitrate oxidised, reduced, neither or both?

thanks in advance

[psyxwar]

Well, there's no change in oxidation number for any of the elements in Ba(NO3)2 right? So neither.

[jack_chay]

oh ok, thank you

[jack_chay]

I have another redox question:

how would you find conjugate oxidant and reductant (redox pairs)

so for example:

a( the conjugate pair when Fe2+ is the oxidant
b( the conjugate pair when Fe2+ is the reductant

thank you

[lzxnl]

Ba(NO3)2(aq) + H2SO4(aq) → BaSO4(s) + 2HNO3(aq)

Is barium nitrate oxidised, reduced, neither or both?

thanks in advance

This is a precipitation reaction, where the barium ions react with sulfate ions to form barium sulfate. No reduction or oxidation occurs; the ions are just bonded differently.

As for your second question, if Fe(II) is the oxidant, it is reduced, so the conjugate pair is Fe metal
If it is the reductant, it is oxidised, so the conjugate pair is Fe(III)

Note: oxidants CAUSE oxidation, are themselves reduced

[jack_chay]

um.. just wondering so is the barium question a precipitation reaction, not a redox at all?

[lzxnl]

Yes. You have bariums ions + sulfate ions => barium sulfate solid.
It's a precipitation reaction; the nitrate and the hydrogen ions don't participate.

[jack_chay]

yup i get it now thank you

[jack_chay]

MnO4-  +  8H  +  5Fe2+  --->    Mn2+  +  4H2O  +  5Fe3+

How would i work out which is the oxidised and which is reduced, because there are three reactants?

Thank you

[Good Will]

If you assign oxidation numbers, we can see that the Fe had an oxidation number of 2+ which changed to a 3+. This means that the Fe has been oxidised and consequently, the MnO4- has been reduced.

[jack_chay]

what about the h?

[psyxwar]

what about the h?

Oxidation number is still one. It goes from H+ to H2O.

[jack_chay]

oh ok thank you everyone

[jack_chay]

What about this equation:

Cd + NiO2 +2H2O ---> Cd(OH)2 + Ni(OH)2

I know Cd is oxidised, Ni doesn't change so H2O is reduced?

[psyxwar]

Nickel does change. It goes from +IV to +II (reduction)