Ncert Exercises & Solutions

Given below are two statements:

Assertion (A):	All the carbon atoms in H 2 C = C = CH 2 are sp²-hybridised.
Reason (R):	In this molecule, all the carbon atoms are attached to each other by double bonds.

1.	Both (A) and (R) are true and (R) is the correct explanation of (A).
2.	Both (A) and (R) are true but (R) is not the correct explanation of (A).
3.	(A) is true but (R) is false.
4.	(A) is false but (R) is true.

Hint: second carbon is sp hybridized

Hybridization can be determined by counting

σ

- bond

\overset{3 σ}{H_{2} C} = \overset{2 σ}{C} = \overset{3 σ}{{CH}_{2}}

3 σ - {sp}^{2} hybridisation

2 σ - sp hybridisation

H_{2} C = C = {CH}_{2}

, the central carbon is sp-hybridised whereas the terminal carbons are sp²-hybridised. Thus, the Assertion is false but the reason is true.