In which of the following changes there is a transfer of 5e–? A) MnO4^...
In which of the following changes there is a transfer of 5e–? A) MnO4^...
Explanation:
In a redox reaction, electrons are transferred from one species to another. The species that loses electrons is said to be oxidized, while the species that gains electrons is said to be reduced. The electrons that are transferred are counted as part of the oxidation number of the species.
In the given options, we need to identify the change that involves a transfer of 5 electrons.
A) MnO4^- → Mn^2+
In this reaction, the Mn atom in MnO4^- changes its oxidation number from +7 to +2. This means that it has gained 5 electrons. Therefore, this reaction involves a transfer of 5 electrons.
B) CrO4^2- → Cr^3+
In this reaction, the Cr atom in CrO4^2- changes its oxidation number from +6 to +3. This means that it has gained 3 electrons. Therefore, this reaction does not involve a transfer of 5 electrons.
C) MnO4^2- → MnO2
In this reaction, the Mn atom in MnO4^2- changes its oxidation number from +7 to +4. This means that it has gained 3 electrons. Therefore, this reaction does not involve a transfer of 5 electrons.
D) Cr2O7^2- → 2Cr^3+
In this reaction, the two Cr atoms in Cr2O7^2- change their oxidation numbers from +6 to +3. This means that each Cr atom has gained 3 electrons. Therefore, this reaction does not involve a transfer of 5 electrons.
Therefore, the correct answer is option A) MnO4^- → Mn^2+.
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