Question

The order of dipole moments of H\textsubscript{2}O (A), CHCl\textsubscript{3} (B) and NH\textsubscript{3} (C) is

• A. B < A < C
• B. B < C < A
• C. C < B < A
• D. C < A < B

Hint:

Dipole moment depends on both molecular shape and electronegativity differences; lone pairs often increase net dipole strength.

Answer 1

The Correct Option is B

Step 1: Dipole moment of H\textsubscript{2O (Water)}
H\textsubscript{2}O has a bent shape with a high difference in electronegativity between O and H strong net dipole. \[ \mu_{\text{H}_2\text{O}} \approx 1.85\ \text{D} \] Step 2: Dipole moment of CHCl\textsubscript{3 (Chloroform)}
Dipole contributions of Cl and H partially cancel each other lower net dipole moment. \[ \mu_{\text{CHCl}_3} \approx 1.01\ \text{D} \] Step 3: Dipole moment of NH\textsubscript{3 (Ammonia)}
NH\textsubscript{3} has a trigonal pyramidal structure with a lone pair, resulting in a moderate dipole. \[ \mu_{\text{NH}_3} \approx 1.47\ \text{D} \] Step 4: Final order
\[ \mu_{\text{CHCl}_3}<\mu_{\text{NH}_3}<\mu_{\text{H}_2\text{O}} \Rightarrow B<C<A \]