5 Fe2+(aq)+MnO41-(aq)+8 H1+(aq)-->5Fe3(aq)+Mn2+(aq)+4 H2O(l)
2 MnO41-(aq)+5 C2O42-(aq)+16 H1+(aq)-> 2 Mn2+(aq)+CO2 g)+8 H2O(l)
Both of these reactions result in the purple permanganate (MnO41-(aq)) ion reacting to form the colourless manganese (II) ion. The difference is that the first reaction happens in a few seconds, while the second occurs over several minutes. Explain why this so, based on what you know of chemical reactions and what you can see in these two reaction equations.
The difference in reaction rates between the two given reactions can be attributed to the different reaction mechanisms and the presence of reactants that influence the reaction kinetics.
In the first reaction, the permanganate ion (MnO41-) is reduced quickly by the Fe2+ ion to form the Mn2+ ion. This rapid reduction occurs because Fe2+ is a strong reducing agent, easily giving up electrons to the MnO41-. Furthermore, the Fe2+ ion is present in excess, ensuring that the reaction proceeds quickly towards completion. The reaction is also facilitated by the presence of acidic conditions, as indicated by the presence of H+ ions in the reaction equation. The acid provides a favorable environment for the reaction by increasing the concentration of H+ ions, which can participate in the reduction process.
On the other hand, the second reaction involves the reduction of permanganate ions by oxalate ions (C2O42-). The reaction is slower because oxalate ions are not as strong of a reducing agent compared to Fe2+. Additionally, the presence of H+ ions in excess (indicated by the 16H+ ions) accelerates the reaction rate due to increased collisions between reactant particles. Since the reaction occurs over several minutes, it suggests that the reaction rate is slower and requires more time for the reduction of permanganate ions to proceed to completion.
Overall, the difference in reaction rates can be attributed to the different strength of the reducing agents (Fe2+ vs. C2O42-), the concentrations of the reactants, and the influence of acidic conditions.
The difference in the reaction rates between the two reactions can be understood by analyzing the reaction equations and the species involved.
In the first reaction, Fe2+(aq), MnO41-(aq), and H1+(aq) are the reactants. Fe2+(aq) is oxidized to Fe3+(aq), while MnO41-(aq) is reduced to Mn2+(aq). This reaction occurs quickly because Fe2+(aq) is a strong reducing agent, meaning it readily donates electrons to other species. Additionally, MnO41-(aq) is a strong oxidizing agent, meaning it readily accepts electrons from other species. These favorable conditions for electron transfer result in a rapid reaction.
In the second reaction, MnO41-(aq), C2O42-(aq), and H1+(aq) are the reactants. MnO41-(aq) is again reduced to Mn2+(aq), but this time C2O42-(aq) is oxidized to CO2(g). The reaction proceeds more slowly in this case because C2O42-(aq) is a weaker reducing agent compared to Fe2+(aq). It is not able to effectively donate electrons to MnO41-(aq) for the reduction reaction to occur quickly. Therefore, the reaction proceeds over several minutes.
In summary, the difference in the reaction rates between the two reactions can be attributed to the differing reactivity of the reducing agents (Fe2+(aq) vs. C2O42-(aq)) and their ability to transfer electrons to the MnO41-(aq) oxidizing agent.