Electronegativity of carbon atoms depends upon their state of hybridisation. In which of the following compounds, the carbon marked with asterisk is most electronegative?
The sp hybridized carbon is highly electronegative as it has more ‘s’ character meaning electrons are closer to nucleus hence held tightly. While other marked carbons are either sp2 or sp3 hybridised. They have more of ‘p’ character. The distribution of electrons in ‘p’ orbital will be above and below the plane of a particular axis so they are not as strongly held as those in ‘s’ orbital .