Label the oxidizing agent and the reducing agent:
a) P4(s) + 5O2(g) -> P4O10(s)
b) Co(s) + Cl2(g) -> CoCl2(s)
c) Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g)
d) PbS(s) + 4H2O2(aq) -> PbSO4(s) + 4H2O(l)
I never learned about oxidation numbers. Thanks!
Student
No problem! To determine the oxidizing agent and reducing agent in each reaction, we need to identify the elements or compounds that undergo oxidation and reduction.
a) P4(s) + 5O2(g) -> P4O10(s)
In this reaction, phosphorus (P) is oxidized from an oxidation state of 0 to +5 in P4O10. Oxygen (O) is reduced from an oxidation state of 0 to -2 in P4O10.
- Oxidizing agent: O2(g)
- Reducing agent: P4(s)
b) Co(s) + Cl2(g) -> CoCl2(s)
In this reaction, cobalt (Co) is oxidized from an oxidation state of 0 to +2 in CoCl2. Chlorine (Cl) is reduced from an oxidation state of 0 to -1 in CoCl2.
- Oxidizing agent: Cl2(g)
- Reducing agent: Co(s)
c) Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g)
In this reaction, iron (Fe) is reduced from an oxidation state of +3 in Fe2O3 to 0 in Fe(s). Carbon (C) in CO is oxidized from an oxidation state of 0 to +4 in CO2.
- Oxidizing agent: Fe2O3(s)
- Reducing agent: CO(g)
d) PbS(s) + 4H2O2(aq) -> PbSO4(s) + 4H2O(l)
In this reaction, lead (Pb) is oxidized from an oxidation state of -2 in PbS to +4 in PbSO4. Hydrogen (H) in H2O2 is reduced from an oxidation state of -1 in H2O2 to 0 in H2O.
- Oxidizing agent: PbS(s)
- Reducing agent: H2O2(aq)
To determine the oxidizing agent and reducing agent in a chemical reaction, you need to identify the elements or compounds that are being oxidized and reduced.
1. In the reaction: P4(s) + 5O2(g) -> P4O10(s)
The element P is initially in its elemental state (P4) and is being oxidized to a higher oxidation state in P4O10. Oxygen (O2) is initially in its elemental state and is being reduced in P4O10. Therefore, in this reaction, P4 is the reducing agent (because it is being oxidized) and O2 is the oxidizing agent (because it is being reduced).
2. In the reaction: Co(s) + Cl2(g) -> CoCl2(s)
Cobalt (Co) is initially in its elemental state and is being oxidized in CoCl2. Chlorine (Cl2) is initially in its elemental state and is being reduced in CoCl2. Therefore, in this reaction, Co is the reducing agent (because it is being oxidized) and Cl2 is the oxidizing agent (because it is being reduced).
3. In the reaction: Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g)
Iron (Fe) in Fe2O3 is initially in its oxidized state (+3) and is being reduced to zero oxidation state in Fe. Carbon monoxide (CO) is initially in its oxidized state (+2) and is being oxidized to +4 in CO2. Therefore, in this reaction, Fe2O3 is the oxidizing agent (because it is causing the oxidation of CO) and CO is the reducing agent (because it is causing the reduction of Fe).
4. In the reaction: PbS(s) + 4H2O2(aq) -> PbSO4(s) + 4H2O(l)
Lead (Pb) in PbS is initially in its elemental state and is being oxidized in PbSO4. Hydrogen peroxide (H2O2) is initially in its oxidized state (-1) and is being reduced to -2 in H2O. Therefore, in this reaction, PbS is the reducing agent (because it is causing the reduction of H2O2) and H2O2 is the oxidizing agent (because it is causing the oxidation of Pb).
Remember, the oxidizing agent is the species that causes oxidation (gets reduced itself) and the reducing agent is the species that causes reduction (gets oxidized itself) in a chemical reaction.
You never learned about oxidation numbers? You missed an important, fundamental lesson.
http://en.wikipedia.org/wiki/Reducing_agent