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Question
The stability of peroxide and superoxide of alkali metals increase as we go down the group. Explain giving reason.
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Solution
As the size of metal ions increases, the stability of peroxides and superoxides increases. Peroxide and superoxide ions combine with a large size of alkali metals. Lithium forms monoxide, sodium forms peroxide and potassium, rubidium and caesium forms superoxide.
\[\ce{Li + O2 -> Li2O}\]
\[\ce{Na + O2 -> Na2O2}\]
\[\ce{K + O2 -> KO2}\]
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