Question

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

• A. Both (A) and (R) are true and (R) is correct explanation of (A)
• B. Both (A) and (R) are true but (R) is not correct explanation of (A)
• C. (A) is true but (R) is not true
• D. (A) is not true but (R) is true

Hint:

Superoxides are stabilized by large alkali metal ions (\(K^+, Rb^+, Cs^+\)) due to low polarization and size compatibility with \(O_2^-\).

Answer 1

The Correct Option is C

Step 1: Check Assertion.
\(K\), \(Rb\), and \(Cs\) form superoxides such as \(KO_2, RbO_2, CsO_2\).
So Assertion (A) is true.
Step 2: Check Reason.
Stability of superoxides increases down the group because larger cations stabilize the larger \(O_2^-\) anion due to lower polarizing power, not due to decrease in lattice energy.
So Reason (R) is not correct.
Step 3: Final decision.
Assertion true, Reason false.
Final Answer:
\[ \boxed{\text{(C)}} \]