s Block Elements JEE Advanced previous year questions with solutions

3 solved JEE Advanced questions on s Block Elements, free to read — no sign-in needed. The full chapter has 4 questions; sign in to attempt the remaining 1 in the exam simulator.

1. Q1JEE Advanced Adv 2020 (Paper 1)
   Which of the following liberates ${O}_{2}$ upon hydrolysis?
   1. A.${Pb}_{3}{O}_{4}$
   2. B.${KO}_{2}$
   3. C.${Na}_{2}{O}_{2}$
   4. D.${Li}_{2}{O}_{2}$
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   Answer: (B)

   $\left(A\right)$ ${Pb}_{3}{O}_{4}+{H}_{2}O\rightarrow$No reaction $(B)$ $2{KO}_{2}+2{H}_{2}O\rightarrow 2KOH+{H}_{2}{O}_{2}+{O}_{2}$ $(C)$ ${Na}_{2}{O}_{2}+2{H}_{2}O\rightarrow 2NaOH+{H}_{2}{O}_{2}$ $(D)$ ${Li}_{2}{O}_{2}+2{H}_{2}O\rightarrow 2LOH+{H}_{2}{O}_{2}$
2. Q2JEE Advanced Adv 2009 (Paper 1)
   The compound(s) formed upon combustion of sodium metal in excess air is (are)
   1. A.$\mathrm{Na}_2 \mathrm{O}_2$
   2. B.$\mathrm{Na}_2 \mathrm{O}$
   3. C.$\mathrm{NaO}_2$
   4. D.$\mathrm{NaOH}$
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   Answer: A,B

   Sodium on heating in air forms both normal oxide and peroxides.
3. Q3JEE Advanced Adv 2007 (Paper 2)
   Statement I Alkali metals dissolve in liquid ammonia to give blue solutions. Statement II Alkali metals in liquid ammonia give solvated species of the type $\left(M\left(\mathrm{NH}_3\right)_n\right]^{+}(M=$ alkali metals $)$.
   1. A.Statement I is true, Statement II is true, Statement II is a correct explanation for Statement I
   2. B.Statement I is true, Statement II is true, Statement II is not a correct explanation for Statement I
   3. C.Statement I is true, Statement II is false
   4. D.Statement $\mathrm{I}$ is false, Statement $\mathrm{II}$ is true
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   Answer: (B)

   Alkali metals in ammonia gives blue colour due to ammoniated $e^{-}$