Oxidizing and Reducing Agents?

k well, Cl is oxidized and thus the reducing agent

MnO4 is reduced and thus the oxidizing agent

It is always the opposite. if something is oxidized it is always the reducing agent. vice versa.

if you have trouble knowing which is which. write out the half equations

Cl-1--->Cl2 and balance it by getting the same amoutn of charges on each side. but first balance atoms.

2Cl-1--->Cl2 + 2e-

the e's are electrons. which makes both sides have a 2- charge.

the other half reaction is a little more difficult because you have oxygens

MnO4-1--->Mn+2

. the list of steps to balancing half reactions is as follows.

balance atoms.

then hydrogen molecules using H+1's

then oxygen using H2O molecules.

then charge with electrons

so start with balance oxygens

MnO4-1-->Mn+2+ 4H2O

4 water's because u need 4 oxygens on that side.

then balance hydrogens with H+1 ions

8H+1 + MnO4-1---> Mn+2 + 4H2O

now finish by balance the charges

the 8 hydrogens have a charge of 8+ and the MnO4 has a charge of -1

thus the reactant side has a charge of +7

the product side has a charge of +2 because of Mn ion.

you want to make the reactant charge equal to product.

Thus you add 5e- to the reactant side... 7-5? equals a charge of +2

Now that you have your half reactions if the electrons are on the reactant side. it is being reduced

if they are on the product side they are oxidized.

just remember this.

LEO

GER

losing elections oxidation

and

gainign electrons reduction

because Cl loses two electrons it is oxidized

and becuase MnO4 gains 5 it is reduced.

Remember : LEO says GER. Lose electron oxidize, gain electron reduce. However, the equation seems to be missing some parts. So, here is an example.

Mg(s) + 2HCl (aq) --> MgCl2 (aq) + H2 (g)

0 +1 -1 +2 -1 0 are the oxidation numbers. You need to know how to identify these to identify the oxidizing and reducing agents.

Mg goes from 0 to +2. It has lost electrons, become more positive, and is therefore oxidized. H went from +1 when it was bonded to chlorine and gained an electron to become a diatomic element with an oxidation number of 0, so it was reduced.

NH4NO2 is ammonium nitrate. It is held together by ionic bonding. When dissolved in water, the ions are less bound to one another and exist as NH4+ (ammonium ion) and NO2- (Nitrate ion) in solution. When writing the formula for a salt (a solid composed of charged species) we write the cation (positive species) before the anion (negative species). This is why table salt is NaCl, and not ClNa. Table salt dissolves to Na+ and Cl-. When a chemical is oxidized it loses electrons. When a chemical is reduced it gains electrons. Remember OIL RIG. (Oxidation Is Loss, Reduction Is Gain.) The chemical, in the equation, being oxidized is also the reducing agent. To gain electrons, they must come from somewhere. The species losing them is therefore reduced. The chemical, in the equation, being reduced is also the oxidizing agent.

remember this....

"reduction means a reduction in charge"

from which this logically follows...

oxidation means an increase in charge

species reduced is the oxiding agent

species oxidized is the reducing agent.

for the agents, think like this.. if one species goes down in charge, it assists the other to go up in charge.. so the species reduced is the oxidizing agent for the other species. same goes for reducing agent...

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now let's look at each charge...

O in MnO4- is -2.. right? O is generally always -2

Mn in MnO4- is +7... because 4x-2 = -8... +7-8 = -2... do you see that?

Cl in Cl- is well -1 right?

Mn+2 is +2

Cl in Cl2 is 0...elements in their "elemental state".. Cl2, H2, F2, O2, Na metal, etc always have a charge = 0

so Mn goes from +7 to +2 and is "reduced"

Cl goes from -1 to 0 and is "oxidized"

Mn is the oxidizing agent

Cl is the reducing agent.

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questions?

here's another example

http://answers.yahoo.com/question/index;_ylt=Ale2A...