Question

Which is not true about the reaction of $K{O_2}$ with $C{O_2}$ and ${H_2}O$
A.In $K{O_2}$, oxidation number of $K$is $ + 1$
B.$K{O_2}$ acts as redundant
C.$K{O_2}$acts as oxidant
D.Oxidation number of carbon does not change during the reaction

Answer 1

Hint:Oxidation number in the simplest terms can be referred to as the charge which an atom or ion of an element carries or appears to carry when present in a combined state with other atoms or ions. It is either equal to the number of groups present on the atom/ ion or the number of valence electrons. To answer this question, you must recall to calculate the change in oxidation state of an element.

Complete answer:
When the oxidation number of an atom or ion increases on course of the reaction, it is said to have been oxidized. It is known as the reducing agent or the reductant. And when the oxidation number of an atom or ion decreases on course of the reaction, it is said to have been reduced. It is known as the oxidizing agent or oxidant.
The reaction of $K{O_2}$ with $C{O_2}$ and ${H_2}O$ is given by:
$4K{O_2} + 2{H_2}O + 4C{O_2} \to 4KHC{O_3} + 3{O_2}$
Potassium being an alkali metal will show an oxidation state of $ + 1$. Oxygen in $O_2^ - $ion gets oxidized from oxidation state of $ - 1/2$to $0$. Since it is getting oxidized, it will act as a redundant.

Thus, the correct answer is B.
Note:
It should be noted that the difference between oxidation number and valency is well understood and the two are not confused. Valency of an element gives the combining capacity of the element. For valence electrons less than 4, the valency is equal to the number of valence electrons and for valence electrons more than 4, the valency is given by subtracting the number of electrons from 8.
Valency cannot have fractional values while oxidation states can. The valency of an atom cannot be equal to zero but oxidation state can.