What is the equivalent weight of Mohr’s salt when it is oxidized by KMnO₄ in acidic medium?
The equivalent weight of Mohr's salt when oxidized by KMnO₄ in acidic medium is the same as its molecular weight, which is 392 g/mol.
Explanation:
Mohr’s Salt and its Molecular Weight:
Mohr's salt has the chemical formula FeSO₄(NH₄)₂·6H₂O. The molecular weight of Mohr's salt is 392 g/mol.
Oxidation of Mohr’s Salt by KMnO₄:
When Mohr's salt is oxidized by KMnO₄ in acidic medium, the iron(II) ions in Mohr's salt are oxidized to iron(III) ions. Each iron(II) ion loses 1 electron and undergoes a change in oxidation state from +2 to +3. This means that the oxidation state of iron increases by 1.
Calculating Equivalent Weight:
Since Mohr's salt contains 1 atom of iron per formula unit, the equivalent weight is equal to the molecular weight divided by the change in oxidation number. In this case, the change in oxidation number is 1.
Conclusion:
Therefore, the equivalent weight of Mohr's salt when oxidized by KMnO₄ in acidic medium is the same as its molecular weight, which is 392 g/mol.