In the given structure, number of sp and sp² hybridized carbon atoms present respectively are :

Solution

Chemistry ma’am · 4 steps

Walk along the chain and count the π bonds on each carbon: one gives sp², two give sp.

1. The rule. A carbon with only single bonds is sp³. A carbon with one double bond is sp². A carbon with a triple bond, or two double bonds, is sp.
2. Read the structure. From left to right the chain is CH₃-CO-CH=CH-CH₂-C≡C-CH=CH-C≡N. That is 10 carbons. The O and N are not carbons, so they do not enter the count.

   Carbon(s)	Bonding	Hybridization
   CH₃ and CH₂	only single bonds	sp³ (2 carbons)
   C=O carbon	one double bond	sp² (1 carbon)
   two CH=CH units	one double bond each	sp² (4 carbons)
   C≡C carbons	triple bond	sp (2 carbons)
   C≡N carbon	triple bond	sp (1 carbon)

3. Add them up. sp carbons: 2 + 1 = 3. sp² carbons: 1 + 4 = 5. Check: 3 + 5 + 2 = 10, which matches the total carbon count.
4. So. There are 3 sp and 5 sp² carbon atoms, which is option (a).

The idea to keep. For hybridization counts, write out the chain, count carbons only, and check that your sp, sp² and sp³ totals add up to the number of carbons.

Answer from the NTA final answer key. Solution by PrepWiser.