The ratio of sp3, sp2 and sp hybridized carbons present in CH3–CH = CH–CN is:
Step 1: Analyze the structure of the molecule:
CH₃–CH = CH–CN is a four-carbon compound. Let us label each carbon for clarity:
- C₁: CH₃ group (methyl group)
- C₂: CH with double bond to C₃
- C₃: CH with double bond to C₂ and single bond to C₄
- C₄: CN group, where C is triple bonded to nitrogen
Structure:
CH₃–CH=CH–C≡N
Step 2: Determine the hybridization of each carbon:
- C₁ (CH₃): forms 4 sigma bonds → sp³ hybridized
- C₂ (CH): involved in one sigma bond with C₁, one sigma bond and one pi bond with C₃ → 3 sigma bonds → sp² hybridized
- C₃ (CH): involved in one sigma bond and one pi bond with C₂, and one sigma bond with C₄ → 3 sigma bonds → sp² hybridized
- C₄ (the carbon in CN): triple bonded to nitrogen → 2 regions of electron density → sp hybridized
Step 3: Count the hybridized carbons:
- sp³: 1 carbon (CH₃)
- sp²: 2 carbons (C₂ and C₃)
- sp: 1 carbon (C in CN group)
Final Answer:
\[
\boxed{1 : 2 : 1}
\]