Chem- Conjugate Redox Pairs (1 Viewer)

hs17

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Is there a specific order when naming/identifying these pairs? Do we have to put either the oxidant or reductant first?
 

Velocifire

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What is this 9000IQ stuff I need to revamp the notes halp :(
 

hs17

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It's not really a major thing but I was still curious if there's a rule to this or not
 

hs17

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Nope it doesn't matter I don't think. Just make sure the product is on the product side, reactant on reactant side then just fill in where the electrons gained/ loss should be. Someone correct me if I'm wrong.
Yay thank you!
 

jazz519

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Not really can write it any order for just stating a redox pair.

But that will change if they ask you to write something like cell notation, then we actually have a set notation:
Zn(s) | Zn2+(aq) || Pb2+(aq) | Pb(s)

For example with that left side is always the anode, right side is always the cathode. the | represent a state change and the || represents the salt bridge
 

hs17

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Not really can write it any order for just stating a redox pair.

But that will change if they ask you to write something like cell notation, then we actually have a set notation:
Zn(s) | Zn2+(aq) || Pb2+(aq) | Pb(s)

For example with that left side is always the anode, right side is always the cathode. the | represent a state change and the || represents the salt bridge
thank you!!!
 

CM_Tutor

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I note that the thread title refers to "conjugate redox pairs"... note that conjugate pairs and redox pairs are not the same thing, and in fact a conjugate pair cannot also be a redox pair and vice versa.

You may not have yet met conjugate pairs, which are part of Lowry-Bronsted theory of acids and basis, but they don't involve redox changes. A common MC question is to give four pairs and to ask which is a conjugate pair, like:

(A) H3O+ / OH

(B) SO3 / HSO3

(C) H2PO4 / H2PO3

(D) HNO2 / NO2
 

hs17

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I note that the thread title refers to "conjugate redox pairs"... note that conjugate pairs and redox pairs are not the same thing, and in fact a conjugate pair cannot also be a redox pair and vice versa.

You may not have yet met conjugate pairs, which are part of Lowry-Bronsted theory of acids and basis, but they don't involve redox changes. A common MC question is to give four pairs and to ask which is a conjugate pair, like:

(A) H3O+ / OH

(B) SO3 / HSO3

(C) H2PO4 / H2PO3

(D) HNO2 / NO2
what would be the answer here? just curious
 

Velocifire

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A - Absolute Answer
B - Best Answer
C - Correct Answer
D - Definite Answer

Oop guess that’s debunked
 

CM_Tutor

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what would be the answer here? just curious
The answer is D.

A gives two species that are conjugates of water, but are not conjugates of each other, which must differ by exactly one H+.

B has two species which differ by a proton and a pair of electrons - that is, by H-

C has two species which differ by an O atom.
 

CM_Tutor

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View attachment 28566
This is what the textbook says...?
It's not a terminology that I have seen used much, and it's not a terminology I would use because of the potential for confusion. It is also unhelpful in that there are multiple oxidation states and results possible in some cases. Cu2+ can be reduced to Cu+ or to Cu. Fe3+ can be reducecd to Fe2+ or to Fe. In organic chemistry, the oxidant MnO4- is reduced to Mn2+ in acidic media and to MnO2 in basic conditions.

In acid/base theory, a conjugate pair is precisely defined - it consists of a species and the species it becomes during a Lowry-Bronsted acid/base reaction. Ammonia is a weak base and reacts in water according to:

NH3 + H2O ---> NH4+ + OH-

Ammonia has acted as a base and accepted a proton, forming its conjugate acid, yielding the conjugate pair NH3 / NH4+
Water has acted as an acid and donated a proton, forming its conjugate base, yielding the conjugate pair H2O / OH-

Whilst some substances (including water) can belong to two different conjugate pairs (the second being H2O / H3O+), there is still no doubt about which pair is present in a given system and what the possible conjugates of a species are. Unfortunately, the same cannot be said for the term "conjugate redox pair" as it is being defined here.

It is worth bearing in mind that textbooks can contain mistakes, as well as describe approaches that are more or less helpful than alternatives. If a teacher / textbook wants to adopt this approach, they are free to do so - but that doesn't make it unambiguous "truth."
 

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