Assertion (A): K, Rb, and Cs form superoxides | vedclass

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(C) Assertion $(A)$ is true: Alkali metals $K$, $Rb$, and $Cs$ react with excess oxygen to form superoxides of the type $MO_2$.Reason $(R)$ is false:

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$(A)$ is true but $(R)$ is not true

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(C) Assertion $(A)$ is true: Alkali metals $K$, $Rb$, and $Cs$ react with excess oxygen to form superoxides of the type $MO_2$.Reason $(R)$ is false: The stability of superoxides increases from $K$ to $Cs$ because the large size of the alkali metal cation stabilizes the large superoxide anion $(O_2^-)$ through a decrease in lattice energy, but the statement claims stability increases *due to* the decrease in lattice energy, which is a misinterpretation of the thermodynamic stability factor. More accurately, the stability increases due to the increasing size of the cation which matches the size of the large anion, reducing the lattice energy and making the formation more favorable. However, the reason provided is scientifically incorrect in its causal link.Therefore, $(A)$ is true but $(R)$ is false.

Assertion $(A)$: $K$, $Rb$, and $Cs$ form superoxides.
Reason $(R)$: The stability of the superoxides increases from $K$ to $Cs$ due to the decrease in lattice energy.
The correct answer is:

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Assertion $(A)$: $K$, $Rb$, and $Cs$ form superoxides.Reason $(R)$: The stability of the superoxides increases from $K$ to $Cs$ due to the decrease in lattice energy.The correct answer is: