In which of the following compounds the carbon marked with asterisk is expected to have greatest positive charge?
In which of the following compounds the carbon marked with asterisk is expected to have greatest positive charge?
The correct option is D ∗CH3−CH2−Cl
Polarisation of σ−bond
When a more electronegative atom is attached to carbon it causes polarisation of σ−bond due to which, partial positive charge is developed on the carbon atom. This polarisation is passed to adjacent carbon atoms with decreased intensity.
So, more the electronegative atom attached, more will be the positive charge developed on neighbouring carbon.
Analysing the options
Option (B)
Polarisation in presence of metal, takes place in such a way that, it creates partial negative charge on neighbouring labelled carbon.
Option (D)
There polarisation does not take place because no electronegative atom is attached to carbon. So, no partial charge development occurs here on labelled carbon.
Option (A)
Option (C)
Carbon marked with an asterisk in compound (A) will have the most positive charge among all options because chlorine atoms are of higher electronegativity than bromine atoms. It has been shown with bigger symbol of delta positive in above figure.
Thus, correct answer is option (A).
∗CH3−CH2−Cl
Polarisation of σ−bond
When a more electronegative atom is attached to carbon it causes polarisation of σ−bond due to which, partial positive charge is developed on the carbon atom. This polarisation is passed to adjacent carbon atoms with decreased intensity.
So, more the electronegative atom attached, more will be the positive charge developed on neighbouring carbon.
Analysing the options
Option (B)
Polarisation in presence of metal, takes place in such a way that, it creates partial negative charge on neighbouring labelled carbon.
Option (D)
There polarisation does not take place because no electronegative atom is attached to carbon. So, no partial charge development occurs here on labelled carbon.
Option (A)
Option (C)
Carbon marked with an asterisk in compound (A) will have the most positive charge among all options because chlorine atoms are of higher electronegativity than bromine atoms. It has been shown with bigger symbol of delta positive in above figure.
Thus, correct answer is option (A).
