Question

Which one of the following is an oxide?
A. \[K{O_2}\]
B. \[Cs{O_2}\]
C. \[Si{O_2}\]
D. \[Ba{O_2}\]

Answer 1

Hint: Oxides are the molecules that have oxygen atoms (one or more than one) in it. In this question, the oxides are of different types. The way oxygen atom bonded to another atom will decide the type of oxide. There are different oxide depending on the bonding of oxygen with other oxygen and other metal in the molecule.

Complete answer:
Oxides and its type are different as the oxygen is bonded in different ways with metal as per the stability of the structure and valence electrons present in the atom in a given molecule.
The different types of oxides are ozonide \[{O_3}^{ - \;}\]. In this oxide, the central oxygen is bonded to another two oxygen on both the sides, the oxygen atom is free to pair up with metal.
superoxide \[{O_2}^ - \], in superoxide the two oxygen atoms are bonded to each other, the electron will be unpaired and it is paramagnetic and thus has a negative one charge on it. They generally react with alkali metal, by reacting with alkali metal superoxide salt is formed. Here, \[K{O_2}\] is generally known as stable superoxide with oxide with alkali meta as potassium. On decomposition in presence of moisture, it gives\[2\;K{O_2}\; + {\rm{ }}2\;{H_2}O\; \to {\rm{ }}2{\rm{ }}KOH{\rm{ }} + \;{H_2}{O_2}\; + \;{O_2}\;\;\]
\[Cs{O_2}\] is also superoxide with and it is paramagnetic as per the property of superoxide ionic form of oxygen is combining with alkali metals which is present in the first group of s-block in periodic table to form superoxide.
\[Ba{O_2}\] is chemically known as barium peroxide. It is a peroxide\[({O_2}^{2 - })\]present in the second group of the s-block which has two electrons in the valence orbital. It will form a peroxide bond with oxide.
\[Si{O_2}\] is the oxide in which the atom is silicon from the p-block which have tendency to form four bonds as it is present in the fourteenth group of p-block with four valence electrons, it is also present in the sand which is highly stable molecule.

Therefore, among all the four only \[Si{O_2}\]is oxide, rest others are either superoxide or peroxide. So, we conclude that the correct answer is (C).

Note:
Here, the different types of oxides formed with different metal and non-metal atoms should be known so that we can easily eliminate the options which are having alkali metals.