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NEET CHEMISTRYClassification of Elements and Periodicity in PropertiesEasy

Question

Which one of the following compounds is a peroxide?

A

KO₂

B

BaO₂

C

MnO₂

D

NO₂

Step-by-Step Solution

To identify the peroxide, we analyze the oxidation state of oxygen and the nature of the oxygen anion in each compound:

  1. BaO₂ (Barium Peroxide): Barium is an alkaline earth metal (Group 2) with a fixed oxidation state of +2. For the compound to be neutral, the O2O_2 group must have a charge of -2 (O22−O_2^{2-}). This is the definition of a peroxide ion. (Ba2+[O−O]2−Ba^{2+} [O-O]^{2-}).
  2. KO₂ (Potassium Superoxide): Potassium is an alkali metal (Group 1) with a +1 charge. The O2O_2 group has a -1 charge (O2−O_2^-), which characterizes a superoxide.
  3. MnO₂ (Manganese Dioxide) & NO₂ (Nitrogen Dioxide): These are normal dioxides where oxygen exists in the -2 oxidation state (O2−O^{2-}). For example, in MnO2MnO_2, Mn is +4 and each O is -2.

Therefore, BaO₂ is the only peroxide among the choices.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Classification of Elements and Periodicity in Properties. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYClassification of Elements and Periodicity in Propertiesfollowingcompoundsperoxide

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