Question

Assertion: Carbon atom is tetravalent though it has two unpaired electrons.

Reason : Carbon has unique ability to form $p\pi -p\pi$ multiple bonds with itself like $C=C,C\equiv C$.

Select the correct option.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is not the correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Answer 1

Answer: (B)

Both A and R are true but R is not the correct explanation of A.

C has atomic number 6. It has 4 electrons in its valence shell. Carbon can either donate all 4 electrons or it can accept 4 electrons to become stable.

Hence it is termed as tetravalent.

Ground state electronic configuration of carbon is $1s^2$, $2s^2$, $2p^2$.

There is a probability of the formation of four bonds is maximum. So, in the formation of one molecule of $C{H}_4$, there will be a combination of 1 C atom with 4 H atoms.

C has uniquely had one of the p-orbitals bonding with the other two p-orbital for making the $\pi -bonds$. Thus p-orbital pointing toward the other atom cannot make $\pi -bond$.

The first member of a group differs from the heavier members in its ability to form pπ - pπ multiple bonds to itself. (carbon)

Both are true, but the reason is not correctly related to the assertion.

Option B is correct.