Question

Assertion: Oxidation number of carbon in ${\mathrm{CH}}_2\mathrm{O}$ is zero.

Reason: ${\mathrm{CH}}_2\mathrm{O}$ (formaldehyde), is a covalent compound.

• A. Assertion is true, but Reason is false.
• B. Both Assertion and Reason are false.
• C. Both Assertion and Reason are true. The reason is the correct explanation of Assertion.
• D. Both Assertion and Reason are true. The reason is not the correct explanation of Assertion.

Answer 1

The correct option is D

Both Assertion and Reason are true. The reason is not the correct explanation of Assertion.

The explanation for the Assertion statement

The oxidation number of carbon in ${\mathbf{CH}}_{\mathbf{2}}\mathbf{O}$ is zero:

• The given molecule is ${\mathrm{CH}}_2\mathrm{O}$ (formaldehyde).
• The oxidation number Oxygen $\left(\mathrm{O}\right)$ is $-2$.
• Let the ation number of carbon $\left(\mathrm{C}\right)$ is $x$.
• The oxidation number of Carbon ${\mathrm{CH}}_2\mathrm{O}$ is as follows :

$\begin{array}{rcl}\mathrm{x}+2\left(1\right)+\left(-2\right)& =& 0\\ \mathrm{x}+2-2& =& 0\\ \mathrm{x}& =& 0\end{array}$

• The oxidation number of carbon in ${\mathrm{CH}}_2\mathrm{O}$ is zero.

The explanation for the Reason statement

${\mathbf{CH}}_{\mathbf{2}}\mathbf{O}$ (formaldehyde), is a covalent compound:

• A chemical bond known as a covalent bond involves the sharing of electron pairs between atoms.
• Formaldehyde is made up of a single carbon atom that has a double bond with an oxygen atom.
• Two hydrogen atoms occupy the last two electron-sharing positions on the carbon.
• Therefore, ${\mathrm{CH}}_2\mathrm{O}$ is a covalent compound.

Therefore, the correct option is (D) Both Assertion and Reason are true. The reason is not the correct explanation for Assertion.