Which of the following molecules has maximum value of dipole moment?
Which of the following molecules has maximum value of dipole moment?
$\mathrm{CH}_3-\mathrm{Cl}$
$\mathrm{CH}_3-\mathrm{O}-\mathrm{CH}_3$
$\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_3$
$\mathrm{CH}_3-\mathrm{CN}$
Solution
The electronegativity of $\mathrm{C} \equiv \mathrm{N}$ bond is highest and $\mathrm{C}-\mathrm{H}$ bond is lowest.
So, the distance between charge separation increases in $\mathrm{CH}_3-\mathrm{CN}$
Dipole moment $=\delta \mathrm{d}$
So, d is largest for $\mathrm{CH}_3-\mathrm{C} \equiv \mathrm{N}$ bond, so dipole moment is highest in $\mathrm{CH}_3-\mathrm{CN}$.