Common Oxidizing and Reducing Agents

G&D Chapter 9 (Extension), Chang Chapter 19

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Oxidizing AgentsSubstances that are __________

For instance• Iron(III) ion• Oxygen• Hydrogen Peroxide• Halogens (chlorine, bromine, iodine)• Dichromate(VI) ion• Manganate(VII) ion (Permanganate ion)

How would you know if this substance was reduced? How would you know the power of an oxidizing agent?

Mild• iron(III) ion yellow-brown iron(lll) to pale green iron(ll)• oxygen not in (aq); yes w/ heat & O2 gas =

combustion

Moderate• hydrogen peroxide (aq) forms water

[note v powerful oxidants can oxidize hydrogen perioxide to oxygen]

• halogens good in (aq) and when heated; more active halogens = better oxidizing agents

– chlorine yellow-green of chlorine to colorless of chloride

– bromine red-brown of bromine to colorless of bromide

– iodine purple-brown of iodine to colorless of iodide

POWERFUL• dichromate(VI) ion orange dichromate(VI) ion to green

chromium(lll) ion

• manganate(VII) ion usu found in acidic conditions

(permanganate ion) purple permanganate(Vll) to colorless manganese(ll)at other pHspurple permanganate(Vll) to brown solid manganese(lV)oxidepurple permanganate(Vll) to dark green manganate(VI) ion

POWERFUL oxidizing agents are typically located on the lower left of a standard electrode potential chart

• hydrogen • carbon and carbon monoxide• iron(II) ion• iodide ion• sulfur dioxide• thiosulfate ion [S2O3

2-]

• metals (Fe, Zn, Mg)

Reducing Agents Substances that are _____________

Mild• hydrogen not for (aq); ok when heated over oxides of

metals

• carbon and carbon monoxide not for (aq); ok when heated over oxides of metals

• iron(II) ion pale green iron(ll) to yellow-brown iron(lll)

• iodide ion colorless of iodide to purple-brown of iodine

• thiosulfate ion [S2O32-] will reduce iodine typically in a starch iodine

complex (black) to colorless of iodide

Moderate to Powerful

• sulfur dioxide colorless sulfur dioxide to colorless sulfate ion

• metals (Mg, Zn, Fe) more reactive = stronger reducing agent

How would you know if this substance was oxidized? How would you know the power of a reducing agent?

POWERFUL reducing agents are typically located on the upper right of a standard electrode potential chart

Assignment

Read Extension – pp 239-240

Do # 1-5

Due: