Chemistry

Oxidation States and Oxides

334 Questions

Oxidation states represent the degree of oxidation of an atom in a chemical compound. This topic covers calculating valency, classifying oxides as acidic or basic, and understanding thermal decomposition. These concepts are frequently tested in chemistry sections across multiple competitive examination platforms.

calculating oxidation statesclassification of oxidesvalency determinationthermal decompositionstability of metal oxides

Oxidation States and Oxides Questions

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

The pair of amphoteric oxides is: 

  1. $VO,\,C{r _2}{O _3}$
  2. ${V _2}{O _5},\,C{r _2}{O _3}$
  3. $V{O _2},\,C{r _2}{O _3}$
  4. ${V _2}{O _5},\,Cr{O _3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
An amphoteric compound is a molecule or ion that can react both as an acid and as a base. Many metals (such as copper, zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. 

Amphoterism depends on the oxidation states of the oxide. Al2O3 is an example of an amphoteric oxide.

 V2O5 and Cr2O3 are amphoteric oxides because both react with alkalies as well as acids.

So, option B is correct
Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the following oxide is most acidic? 

  1. $Na _2O$
  2. $MgO$
  3. $SiO _2$
  4. $Cl _2O _7$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$Na _2O$ , MgO are basic oxides.

$Cl _2O _7$  has highest acidity because it is an oxide of non metal .
Non metallic oxides are acidic 
This oxide reacts with water to give $HClO _4$ i,e,. strong acid.
So, 

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

An element $X$ which occurs in the second period has an outer electronic structure $s^{2}p^{2}$. The formula and acid-base character of its oxide, respectively are,

  1. $XO _{3}$, basic
  2. $X _{2}O _{3}$, basic
  3. $X _{2}O _{3}$, amphoteric
  4. $XO _{2}$, acidic
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The outer electronic configuration given is $ns^2np^2$. It is the configuration of the Carbon family. So we know that non-metal oxides are acidic and have general formula $XO _2$.
Option D is correct.
Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the oxide gives two oxyacid in water ?

  1. ${N _2}{O _3}$
  2. $NO$
  3. $N{O _2}$
  4. ${P _4}{O _{10}}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Oxyacid, any oxygen-containing acid. Most covalent nonmetallic oxides react with water to form acidic oxides; that is, they react with water to form oxyacids that yield hydronium ions (H3O+) in solution. There are some exceptions, such as carbon dioxide, CO, nitrous oxide, N2O, and nitric oxide, NO.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which one of the following is normal oxide?

  1. $K{O _2}$
  2. $Ba{O _2}$
  3. $Si{O _2}$
  4. $Cs{O _2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A normal oxide contains the O(2-) ion. SiO2 is a covalent network solid that behaves as a normal acidic oxide. KO2 and CsO2 are superoxides, and BaO2 is a peroxide.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the following is/are peroxide(s) ?

  1. $ PbO _{2} $
  2. $ H _{2}O _{2} $
  3. $ SrO _{2} $
  4. $ BaO _{2} $
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

In $ {PbO} _{2}, $ Its $ Pb^{+4}$ & $ 2O^{-2} $


In $ {H _{2}O} _{2},$ there is peroxide linkage

$ H-O-O-H $ 

In $ SrO _{2}, $ as Sr is alkaline earth metal 
$ \therefore $ Its $ Sr^{2+} $

$ \therefore $ Its $ O _{2}^{-2}, (\bar{O}-\bar{O}) $ peroxide linkage 

In $ BaO _{2},$ Its $ Ba^{{+2}}\therefore O _{2}^{-2} $

$ \bar{O}-\bar{O} $ peroxide linkage 

Hence, the correct options are $\text{B}$, $\text{C}$ and $\text{D}$

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the following oxides is amphoteric in character?

  1. $CaO$
  2. $CO _2$
  3. $SiO _2$
  4. $SnO _2$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Option (D) is correct.
$SnO _2$ is amphoteric in character.
$SnO _2 + 2NaOH \rightarrow Na _2SnO _3 + H _2O$
$SnO _2 + 4HCl \rightarrow SnCl _4 + 2H _2O$+$CO _2$ is acidic in character.
$SiO _2$ is very weak acid.
$CaO _2$ is basic in nature.
Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the following oxides is/are not amphoteric in character?

  1. CaO
  2. $CO _2$
  3. $SiO _2$
  4. $SnO _2$
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

$CaO$, $CO _2$ and $SiO _2$ when dissolved in water gives base ,hence they are basic oxides.


$SnO _2$ do not react with water, so it is amphoteric. 

Hence options A,B, & C are correct.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the following oxides are not neutral?

  1. $CO$
  2. $SnO _2$
  3. $ZnO$
  4. $SiO _2$
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

 $CO$ is a neutral oxide insoluble in water, but behaves as amphoteric compound. 


$SiO _2$ amphoteric oxide, $SnO _2$ basic oxide and  $ZnO$  is amphoteric oxide.

Hence options B,C & D are correct.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Select the correct statements:

  1. s-block metal oxides are basic in nature, except $BeO$ which is amphoteric.
  2. p-block metal oxides are acidic in nature, except $NO$,$ N _2O$,$ CO$.

  3. d-block metal oxides are basic, acidic, and amphoteric in nature.

  4. d-block metal oxides are only basic in nature.
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

(A) BeO is amphoteric in nature. It reacts with acids as well as alkalies.  Oxides of other s block metal elements are basic in nature. They react only with acids. hence, the option A is correct.

(B) The oxides $NO, N _2O,CO$   are neutral. Whereas the  remaining oxides of p block metals are acidic in nature. Thus, the option B is correct.

Some of the d block metal oxides are basic in nature, some of them acidic in nature where as the rest are amphoteric in nature. Thus, the option C is correct and option D is incorrect.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

The species that do not contain peroxide ions is :

  1. $PbO _2$
  2. $H _2O _2$
  3. $SrO _2$
  4. $BaO _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Only true peroxides which have -O-O- bond give hydrogen peroxide with dilute acids.
$PbO _2$ does not give hydrogen peroxide with dilute acids. So it is not a true peroxide.

Hence option A is correct.