Selected Redox Reactions

Date Performed: March 14, 2013

Selected RedOx Reactions

Institute of Chemistry, College of Science

University of the Philippines, Diliman, Quezon City, Philippines

Received March 19, 2013

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RESULTS AND DISCUSSION

In this experiment, three chemical systems exhibiting a Reduction-Oxidation reaction, or a RedOx reaction, are put under observation. Following the Law of Conservation, matter is neither created nor destroyed; it is merely rearranged. The same goes for RedOx reactions, however, additional considerations are taken into account. Basically, a RedOx reaction also notes how electrons are transferred from one species to another. A RedOx reaction also takes the charges of the ions into consideration. In a RedOx reaction, the species that loses electrons is said to have been oxidized, and is the reducing agent of the species that was reduced. Likewise, a species that gained electrons is said to have been reduced, and becomes the oxidizing agent of the species that underwent oxidation.

The first system put under study is the RedOx reaction undergone by the Sulfite and Permanganate ions in neutral, basic, and acidic media. The effect of pH on the system is also part of the study. In neutral media, the RedOx reaction is represented by the following chemical (divided into the oxidation and reduction half-reactions) equation:

Oxidation half-reaction:

SO3(aq)2-+ →SO4(aq)2-

Reduction half-reaction:

MnO4(aq)-→ MnO2(s)

When put together and balanced, yields the following net ionic equation:

2H(aq)++2MnO4 (aq)-+3SO3(aq)2-→2MnO2(s)+ H2Ol+3SO4(aq)2-

This reaction yielded a colorless solution with a brown precipitate. The permanganate ion gains electrons, and is said to have been reduced to Manganese Dioxide, which a brown-black insoluble solid, hence the observed loss of the notable purple color of the permanganate ion, and the observed formation of a brown...