BTEC APPLIED SCIENCE LAB REPORT ON OXIDATION AND REDUCTION.

BTEC APPLIED SCIENCE LAB REPORT ON OXIDATION AND REDUCTION. FND04: FURTHER CHEMISTRY FOR BIOSCIENCES - LAB REPORT Oxidation and Reduction (REDOX) Reactions Introduction Oxidation-reduction reactions, otherwise known as redox reactions, are fundamentally a process that involves a transfer of electrons. Oxidation can be defined as loss of electrons and reduction as gain of electrons. Therefore, oxidation results in an increase in oxidation number and reduction a decrease in oxidation number (Gent and Ritchie, 2007). In a redox reaction, the substance that is reduced is called an oxidising agent as it gains electrons from the substance that is oxidised. In contrast, a reducing agent loses electrons so it itself is oxidised whilst reducing another substance (Gent and Ritchie, 2008). Although oxidation and reduction reactions can be viewed separately through half-equations, reduction and oxidation occur simultaneously forming a whole reaction (Haustein, 2014). The total number of electrons lost must equal the total electrons gained in a redox reaction in order to maintain neutrality. The half equations can be combined to construct a balanced full net ionic equation. For instance, in the reaction of iron (III) chloride and tin (II) chloride, the iron is being reduced and the tin is being oxidised. The chloride ions are unaffected and are known as spectator ions. Fe3+ + e-  Fe2+ Reduction Sn2+  Sn4+ + 2e- Oxidation The following half equations can be combined by balancing them through multiplying the coefficients in the reduction equation by 2. Followed by adding the balanced half equations together. (Blackman et al., 2015) Substances that have a large affinity for electrons tend to be good oxidising agents such as potassium manganate and the halogens. In comparison, metals are usually good reducing agents as they have a strong tendency to lose electrons (Gent and Ritchie, 2007). Redox agents are responsible for the visible colour changes as well as changes in property in some instances. This is because a colour change indicates that a chemical reaction has taken place. Furthermore, the products of a redox reaction c