Question

A diatomic molecule has a dipole moment of $1.2$ D if its bond distance is $100$ pm. What partial electronic charge e exists on each atom?

• A. $20$% of e
• B. $21$% of e
• C. $19$% of e
• D. $25$% of e

Answer 1

The correct option is D $25$% of e

Let the electronic charge on each atom be $x$.

The dipole moment is $1.2D$

We know, $1D={10}^{-18}esu.cm$

The dipole moment in esu cm units is $1.2\times {10}^{-18}esu.cm$

The dipole moment is the product of its charge and the inter atomic distance.

It would be $x\times 100\times {10}^{-10}=1.2\times {10}^{-18}$

$x=1.2\times {10}^{-10}esu$

But the electronic charge $e=4.8\times {10}^{-10}esu$

Partial electronic charge on each atom $=\frac{1.2\times {10}^{-10}esu}{4.8\times {10}^{-10}esu}\times 100$

$x=25$ % of e