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 structure of the atom electronic configuration and valency electron configuration periodic trends in physical properties

Valency of magnesium and oxygen in $MgO$ is:

  1. one and one

  2. two and two

  3. one and two

  4. two and one
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ans. $(B)$ $(two$ $and$ $two)$

This is because magnesium loses two electrons to have an octet and oxygen gains two electrons to have an octet. The final formula of magnesium oxide is ${MgO}$. So, the valencies magnesium and oxygen in $ {MgO}$ are $2$ and $2$ .
Multiple choice chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

What is the oxidation state of Phosphorus in ${P}{Cl} _{3}$?

  1. ${+}{5}$
  2. ${+}{3}$
  3. ${+}{1}$
  4. ${-}{3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The oxidation state of ${P}$ in ${P}{Cl} _{3}$ is ${+3}$.
Each Chlorine atom has an oxidation number of ${-1}$. There are three chlorine atoms, hence the total oxidation number of the Chloride ions in ${-3}$. ${PCl} _{3}$ molecule is neutral. Hence the oxidation number of Phosphorus should be ${+3}$

Multiple choice chemistry d- and f-block elements actinoids the actinoids the d-and f-block elements comparison of lanthanoids and actinoids

Which of the following forms stable oxidation state?

  1. Ce+ , Yb+

  2. Eu + , Tb+

  3. Lu+, Gd

  4. Pr5+ ,Nd2+
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cerium (Ce) and Ytterbium (Yb) can exhibit stable +4 and +2 oxidation states respectively due to stable electronic configurations (f0 and f14), making Ce+ and Yb+ (or their related stable ions) notable in lanthanide/actinide chemistry contexts.

Multiple choice chemistry d- and f-block elements actinoids the actinoids the d-and f-block elements comparison of lanthanoids and actinoids

Amphoteric behaviour is shown by the oxides of :

  1. $Al$ and $Ca$
  2. $Pb$ and $Ba$
  3. $Cr$ and $Mg$
  4. $Sn$ and $Zn$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amphoteric oxides can behave as an acid as well as base. They react with both acids and bases to form salts. Tin oxide although doesn't dissolve in water but it is amphoteric in nature. Zinc oxide is also amphoteric in nature.

$ZnO+HCl \rightarrow ZnCl _2+H _2O$
$ZnO+NaOH \rightarrow Na _2ZnO _2+H _2O$
$SnO _2+HCl \rightarrow SnCl _4+H _2O$
$SnO _2+NaOH+H _2O \rightarrow Na _2[Sn(OH) _6]$

Multiple choice chemistry lattice energy defining lattice energy ionic or electrovalent bond energy cycles

The lattice energies of the oxidies of $Mg,Ca,Sr \;$ and $\;Ba$ follow the order:

  1. $BaO\;>\;SrO\;>\;CaO\;>MgO$
  2. $CaO\;>\;BaO\;>\;SrO\;>\;MgO$
  3. $MgO\;>\;SrO\;>\;CaO\;>\;BaO$
  4. $MgO\;>\;CaO\;>\;SrO\;>\;BaO$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For oxides of the same group (alkaline earth metals), the lattice energy decreases as the size of the cation increases. Since the ionic radii follow Mg2+ < Ca2+ < Sr2+ < Ba2+, the lattice energy follows MgO > CaO > SrO > BaO.

Multiple choice aluminium patterns and properties of metals chemistry

X$ _2$O$ _3$ is produced if ratio of element to oxygen is 2:3 in the reaction of element and oxygen,what is that element?

  1. Ca

  2. Li

  3. Al

  4. F

  5. C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\displaystyle   X _2O _3$ is produced if ratio of element to oxygen is 2:3 in the reaction of element and oxygen, that element is Aluminum (Al). It forms $\displaystyle   Al _2O _3$ . The valence of Al (and X)  is +3 and that of oxygen is -2.
Ca, Li, F and C have valencies +2, +1, -1 and 4 respectively.

Multiple choice chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

Which of the following statement is correct regarding the compound ${\text{''}}\left[ {{{\left( {{\text{CO}}} \right)} _{\text{3}}}{\text{Fe}}{{\left( {{\text{CO}}} \right)} _{\text{3}}}{\text{Fe}}{{\left( {{\text{CO}}} \right)} _{\text{3}}}} \right]{\text{'}}$

  1. The ${{\text{d}} _{{\text{C - O}}}}$ (bridging) is greater than ${{\text{d}} _{{\text{C - O}}}}$ (terminal)

  2. The bond order of bridging C-O bond is greater than that of terminal C-O bond

  3. The E.A.N. value of each Fe-atom is 35

  4. the oxidation state of Fe in this complex is (-1)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In Fe3(CO)12, bridging CO ligands have a lower bond order than terminal CO ligands because they participate in more extensive back-bonding, resulting in a longer C-O bond length for bridging ligands.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

The oxidation number of hydrogen varies from:

  1. -1 to +1

  2. 0 to +1

  3. -1 to 0

  4. 0 to +2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electronic configuration of the hydrogen atom is $1s^{1}$. So, it can act as an electron acceptor to complete its' outer orbital as well as it can act as an electron donor to donate its' outermost electron to gain stability like metals.


In hydrides like$NaH$, $H$ occurs in $-1$ state.
In acids as well as oxides, $H$ occurs in $+1$ state.

Therefore its' oxidation state varies from $-1$ to $+1$.

Multiple choice zoology ecosystem : structure and function biogeochemical cycles - sedimentary biogeochemical cycle nitrogen and phosphorus cycles

Phosphorus cycles in the form of ____________.

  1. $HPO^{3-}$
  2. $P^{2}$ (gas)
  3. $PO _{4}^{3-}$
  4. $Al _{2}(PO _{4}) _{3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Phosphorus is obtained from soil as orthophosphate $(PO _{4}^{3-})$. Organic phosphorus circulates in nature from plants to animals. Phosphate is released by decomposers (Phosphatising bacteria) back to soil.

Multiple choice chemistry production of metals extraction of aluminium metallurgy of aluminium extraction of metals by electrolysis

Anodic product in the electrolytic reduction of alumina:

  1. $CO _2, O _2$
  2. $O _2$
  3. $F _2$
  4. $O _2,F _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ionization of Alumina in Electrolytic refining.

$2Al _2O _3\longrightarrow 6O^{-2}+Al^{3+}$
Reaction at cathode
$4Al^{3+}+12e^{-}\longrightarrow 4Al$
Reaction at anode
$6O^{-2}\longrightarrow 3O _2+12e^-$
$O _2$ is released at anode.