Chapter 13, Problem 13.54QP

Interpretation Introduction

Interpretation: The oxidation state of carbon atoms of the given molecules indicated with arrows is to be identified.

Concept introduction: The oxidation state of an atom in a molecule is defined as the degree to which the atom loses electrons in a molecule. The value of oxidation state can be positive, negative or zero.

To determine: The oxidation state of carbon atoms of the given molecules indicated with arrows.

Answer to Problem 13.54QP

The value of oxidation for the carbon atom indicated by arrow (a) is $-3$ and the value of oxidation for the carbon atom indicated by arrow (b) is $-2$.

The oxidation state of carbon indicated by arrow (c) is $-2$ and the oxidation state of carbon indicated by arrow (d) is $-2$.

The oxidation state of carbon indicated by arrow (e) is $-1$ and the oxidation state of carbon indicated by arrow (f) is $0$.

Explanation of Solution

The given molecules are,

Figure 1

The oxidation state of carbon indicated by arrow (a) is calculated by the formula,

$\text{Number}\text{of}\text{H}\text{atoms}\left(\text{Charge}\text{on}\text{H}\right)+x_{\text{a}}+\text{Number}\text{of}\text{C}\text{atoms}\left(\text{Charge}\text{on}\text{C}\right)=0$

Where,

• $x_{\text{a}}$ is the oxidation state of carbon atom indicated by arrow (a).

Substitute the value of number and charge of hydrogen and carbon atoms in the above equation.

$\begin{array}{c}3\left(+1\right)+x_{\text{a}}+1\left(0\right)=0\\ +3+x_{\text{a}}+0=0\\ x_{\text{a}}=-3\end{array}$

Hence, the oxidation state of carbon indicated by arrow (a) is $-3$.

The oxidation state of carbon indicated by arrow (b) is calculated by the formula,

$\text{Number}\text{of}\text{H}\text{atoms}\left(\text{Charge}\text{on}\text{H}\right)+x_{\text{b}}+\text{Number}\text{of}\text{C}\text{atoms}\left(\text{Charge}\text{on}\text{C}\right)=0$

Where,

• $x_{\text{b}}$ is the oxidation state of carbon atom indicated by arrow (b).

Substitute the value of number and charge of hydrogen and carbon atoms in the above equation.

$\begin{array}{c}2\left(+1\right)+x_{\text{a}}+2\left(0\right)=0\\ +2+x_{\text{a}}+0=0\\ x_{\text{a}}=-2\end{array}$

Hence, the oxidation state of carbon indicated by arrow (b) is $-2$.

The oxidation state of carbon indicated by arrow (c) is calculated by the formula,

$\text{Number}\text{of}\text{H}\text{atoms}\left(\text{Charge}\text{on}\text{H}\right)+x_{\text{c}}+\text{Number}\text{of}\text{C}\text{atoms}\left(\text{Charge}\text{on}\text{C}\right)=0$

Where,

• $x_{\text{c}}$ is the oxidation state of carbon atom indicated by arrow (c).

Substitute the value of number and charge of hydrogen and carbon atoms in the above equation.

$\begin{array}{c}2\left(+1\right)+x_{\text{c}}+1\left(0\right)=0\\ +2+x_{\text{c}}+0=0\\ x_{\text{c}}=-2\end{array}$

Hence, the oxidation state of carbon indicated by arrow (c) is $-2$.

The oxidation state of carbon indicated by arrow (d) is calculated by the formula,

$\text{Number}\text{of}\text{H}\text{atoms}\left(\text{Charge}\text{on}\text{H}\right)+x_{\text{d}}+\text{Number}\text{of}\text{C}\text{atoms}\left(\text{Charge}\text{on}\text{C}\right)=0$

Where,

• $x_{\text{d}}$ is the oxidation state of carbon atom indicated by arrow (d).

Substitute the value of number and charge of hydrogen and carbon atoms in the above equation.

$\begin{array}{c}2\left(+1\right)+x_{\text{d}}+2\left(0\right)=0\\ +2+x_{\text{d}}+0=0\\ x_{\text{d}}=-2\end{array}$

Hence, the oxidation state of carbon indicated by arrow (d) is $-2$.

The oxidation state of carbon indicated by arrow (e) is calculated by the formula,

$\text{Number}\text{of}\text{H}\text{atoms}\left(\text{Charge}\text{on}\text{H}\right)+x_{\text{e}}+\text{Number}\text{of}\text{C}\text{atoms}\left(\text{Charge}\text{on}\text{C}\right)=0$

Where,

• $x_{\text{e}}$ is the oxidation state of carbon atom indicated by arrow (e).

Substitute the value of number and charge of hydrogen and carbon atoms in the above equation.

$\begin{array}{c}1\left(+1\right)+x_{\text{e}}+1\left(0\right)=0\\ +1+x_{\text{e}}+0=0\\ x_e=-1\end{array}$

Hence, the oxidation state of carbon indicated by arrow (e) is $-1$.

The oxidation state of carbon indicated by arrow (f) is calculated by the formula,

$\text{Number}\text{of}\text{H}\text{atoms}\left(\text{Charge}\text{on}\text{H}\right)+x_{\text{f}}+\text{Number}\text{of}\text{C}\text{atoms}\left(\text{Charge}\text{on}\text{C}\right)=0$

Where,

• $x_{\text{f}}$ is the oxidation state of carbon atom indicated by arrow (f).

Substitute the value of number and charge of hydrogen and carbon atoms in the above equation.

$\begin{array}{c}0\left(+1\right)+x_{\text{f}}+2\left(0\right)=0\\ 0+x_{\text{f}}+0=0\\ x_{\text{f}}=0\end{array}$

Hence, the oxidation state of carbon indicated by arrow (f) is $0$.

Conclusion

The value of oxidation for the carbon atom indicated by arrow (a) is $-3$ and the value of oxidation for the carbon atom indicated by arrow (b) is $-2$.

The oxidation state of carbon indicated by arrow (c) is $-2$ and the oxidation state of carbon indicated by arrow (d) is $-2$.

The oxidation state of carbon indicated by arrow (e) is $-1$ and the oxidation state of carbon indicated by arrow (f) is $0$.