Question

Which of the following compounds have zero oxidation state at carbon?
This question has multiple correct options
A. ${C_6}{H_{12}}{O_6}$
B. $HCOOH$
C. $HCHO$
D. $C{H_4}$

Answer 1

Oxidation state is also known as oxidation number. It is equal to the number of electrons which an atom gains or losses to form a bond. Oxidation state tracks the transfer of electrons during a chemical reaction.

Complete step by step answer: Carbon is an element in the periodic table with atomic number 6. The electronic configuration of carbon is $1{s^2}2{s^2}2{p^2}$. The valence shell or outermost shell of carbon is two which contains a total of four electrons, i.e. two in $2s$ and two in $2p$. A total of four electrons are available for bond formation with carbon atoms.
The question asks to find the zero oxidation state in a carbon atom. All the given molecules are neutral molecules carrying no charge. Thus the overall charge of every molecule is zero.
Let us consider the molecules one by one to determine the oxidation state. Let $x$be the oxidation state of carbon.
The atomic number of hydrogen is one. So for making a bond it can donate only one electron so it carries a unit positive charge. The atomic number of oxygen is $8$. It has the electronic configuration of $1{s^2}2{s^2}2{p^4}$. The valence shell contains $6$ electrons, two in $2s$ and four in $2p$. In order to complete the octet the oxygen atom requires two electrons. So the charge on the oxygen atom will be $- 2$.
${C_6}{H_{12}}{O_6}$: $x \times 6 + 12( + 1) + 6( - 2) = 0$
$6x + 12 - 12 = 0$
$6x = 0$
$x = 0.$
The oxidation state of carbon is$0$.
$HCOOH$: $x + 2( + 1) + 2( - 2) = 0$
$x + 2 - 4 = 0$
$x = 2.$
The oxidation state of carbon is$2$.
$HCHO$: $x + 2( + 1) + 1( - 2) = 0$
$x + 2 - 2 = 0$
$x = 0.$
The oxidation state of carbon is$0$.
$C{H_4}$: $x + 4( + 1) = 0$
$x + 4 = 0$
$x = - 4.$
The oxidation state of carbon is$- 4$.
Hence option A and C are the correct answers, i.e. ${C_6}{H_{12}}{O_6}$ and $HCHO$ are the compounds which have zero oxidation state at carbon.

Note: The more electronegative atom accepts electrons and less electronegative atom donates electrons. The loss of electrons is called oxidation and the gain of electrons called reduction.