Electronegativity of carbon atoms depends upon their state of hybridisation. In which of the following compounds, the carbon marked with asterisk is most electronegative?

Correct answer: 3) 

Concept:

• Electronegativity of carbon atoms depends on their state of hybridization.
• By Determining the hybridization of each carbon atom marked with an asterisk we can decide the most electronegative carbon atom.
•  More the s-character, the more the electronegativity of the carbon atom.
• Thus, the sp hybridized carbon atom is the most electronegative because the contribution of s and p orbitals is 50 %.

Explanation:

• Electronegativity of carbon depends upon the state of hybridization.
• As the percentage of s-character in the hybridization of carbon atoms increases, the electronegativity increases.
• Electronegativity increases as the state of hybridization changes from sp³ to sp² to sp.
• Therefore, sp-carbon has the highest electronegativity.
• sp Hybridized carbon is the most electronegative.
• It has 50% s-character.
• So, the carbon marked with the asterisk of compound (C) is sp hybridized.
• Thus, this carbon is the most electronegative among the given compounds with 50% s−character.
• The asterisk marked carbon in CH3 – CH2 – C ≡ *CH  is sp hybridised.
• Hence, it is most electronegative.

Conclusion:

Thus, The asterisk marked carbon in CH3 – CH2 – C ≡ *CH  is sp hybridized. Hence, it is most electronegative.

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