Exams › JEE Advanced › Chemistry
Which of the following compounds releases O2 gas upon hydrolysis?
- Pb3O4
- KO2
- Na2O2
- Li2O2
Correct answer: KO2
Solution
KO2 is potassium superoxide, containing the O2⁻ ion. It reacts with water: 4KO2 + 2H2O -> 4KOH + 3O2. This liberates oxygen gas. Na2O2 (sodium peroxide) reacts with water to give NaOH and H2O2, not O2 directly (H2O2 can decompose to O2 slowly but the primary product is H2O2). Li2O2 and Na2O2 give peroxide ions. Pb3O4 is a mixed oxide (PbO + PbO2) and does not liberate O2 on hydrolysis. Only KO2 directly produces O2 upon hydrolysis.
Related JEE Advanced Chemistry questions
- When carbonates from the s-block break down, a gas is released that is denser than air and extinguishes a burning splint. Identify the gas.
- What is the classification of Be2C and Al4C3 based on their chemical composition?
- When heated, magnesium nitrate and barium nitrate break down as follows: 2M(NO3)2 → heat → 2MO + 4NO2(g) + O2(g) (where M = Mg or Ba). Which statement is accurate regarding their decomposition behavior?
- Consider the following reactions of Group IA (alkali) metals with liquid ammonia: M + (x+y) NH3 -> [M(NH3)ₓ]+ + [e(NH3)_y]- [M(NH3)ₓ]+ + e-(in NH3) -> M-NH2(aq) + (1/2) H2(g) Which of the following statements about these solutions is INCORRECT?
- How many of the following elements give a characteristic flame test color: Li, Na, K, Be, Mg, Ca, Ba, Cs?
- Arrange the following carbonates in the correct increasing order of their thermal stability: BeCO3, MgCO3, CaCO3, K2CO3.
⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →