What is the change in electrons for manganese in the following reaction? 2 MnO4 (aH2 0 2(a)+6H (aq)2 M 9)+4H2 0u) ()+302( Li Be V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr La Ce Pr Nd Pm Sm Eu Gd Tb Ho Er Tm Yb Ac Th Pa U Pu Am Cm Bk Cf Es Fm Md No OA. Gain 5 electrons O B. Lose 1 electrons O C. Lose 2 electrons D. Gain 3 electrons
The Correct Answer and Explanation is :
To determine the change in the number of electrons for manganese in the reaction:
- Understand the oxidation states:
- Permanganate ion (( \text{MnO}_4^- )): Manganese has an oxidation state of ( +7 ) because oxygen has an oxidation state of ( -2 ), and the overall charge of the ion is ( -1 ).
- Manganese ion (( \text{Mn}^{2+} )): Manganese has an oxidation state of ( +2 ).
- Analyze the change in oxidation state:
- Manganese starts at ( +7 ) in ( \text{MnO}_4^- ).
- Manganese ends at ( +2 ) in ( \text{Mn}^{2+} ).
- The change in oxidation state is ( +7 – (+2) = +5 ).
- Electrons involved:
- A decrease in the oxidation state means manganese gains electrons.
- The gain is ( 5 ) electrons per manganese atom.
- Reaction context:
- The reaction balances to ensure that the number of electrons lost and gained are equal. In this case, the oxidation of ( H_2O_2 ) to ( O_2 ) complements the reduction of ( \text{MnO}_4^- ) to ( \text{Mn}^{2+} ).
Correct Answer: A. Gain 5 electrons
Explanation:
In redox reactions, oxidation refers to the loss of electrons, and reduction refers to the gain of electrons. Here, ( \text{MnO}_4^- ) undergoes reduction. Starting in an oxidation state of ( +7 ), manganese reduces to ( +2 ), indicating a net gain of ( 5 ) electrons per manganese atom.
This process highlights the balance between oxidizing and reducing agents. ( \text{MnO}_4^- ) acts as an oxidizing agent, and ( H_2O_2 ), which is oxidized to ( O_2 ), acts as the reducing agent. The reaction’s stoichiometry ensures electron conservation, aligning with the principles of redox chemistry.