Which oxide of manganese is amphoteric?

Manganese oxides exhibit a variety of chemical behaviors depending on their oxidation states. Among them, manganese dioxide (MnO₂) is amphoteric, which means it can react with both acids and bases.
In acidic conditions, MnO₂ reacts with strong acids such as HCl... Read More

1 INORGANIC CHEMISTRY MCQS

Which oxide of manganese is amphoteric?

  • MnO₂
  • Mn₂O₃
  • Mn₂O₇
  • MnO
Correct Answer: A. MnO₂

Detailed Explanation

Manganese oxides exhibit a variety of chemical behaviors depending on their oxidation states. Among them, manganese dioxide (MnO₂) is amphoteric, which means it can react with both acids and bases.


In acidic conditions, MnO₂ reacts with strong acids such as HCl or H₂SO₄ to produce manganese(II) salts and chlorine or oxygen depending on the reaction:


MnO₂ + 4HCl → MnCl₂ + Cl₂ + 2H₂O


In basic conditions, MnO₂ reacts with strong bases like sodium hydroxide (NaOH) in the presence of an oxidizing agent to form manganates:


2MnO₂ + 4NaOH + O₂ → 2Na₂MnO₄ + 2H₂O


Other oxides of manganese are not amphoteric:




  • Mn₂O₃ is mainly basic.




  • Mn₂O₇ is strongly acidic.




  • MnO is basic.




The amphoteric nature of MnO₂ is significant in inorganic chemistry because it demonstrates how oxidation states affect chemical reactivity. MnO₂ is widely used as an oxidizing agent, in the manufacture of batteries, and in industrial chemical reactions.


Understanding amphoterism helps students relate metal oxides, acid-base reactions, and redox chemistry, which are key concepts in the study of inorganic compounds and transition metals. Recognizing that MnO₂ can act both as a base and an acid illustrates the versatile chemical behavior of transition metal oxides.




 

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