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MHT CET202619 April 2026Morning ShiftChemistrys Block ElementsActual

Which element from following forms superoxide with oxygen?

Options

  1. ASodium
  2. BPotassium
  3. CLithium
  4. DMagnesium

Correct answer

B. Potassium

Step-by-step solution

Alkali metals react with oxygen to form different types of oxides depending on their size. Lithium forms mainly monoxide ( Li₂O ). Sodium forms mainly peroxide ( Na₂O₂ ). Potassium, rubidium, and cesium form mainly superoxides ( MO₂ ) due to the stabilization of the large superoxide ion by large cations. Magnesium forms mainly monoxide ( MgO ). Therefore, potassium forms a superoxide with oxygen. Answer: Potassium

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