Question

Number of compounds from the following with zero dipole moment is _______.
HF, H$_2$, H$_2$S, CO$_2$, NH$_3$, BF$_3$, CH$_4$, CHCl$_3$, SiF$_4$, H$_2$O, BeF$_2$

Answer 1

Correct Answer: 6

A molecule has a zero dipole moment if it is symmetric, and the bond dipoles cancel each other out. Let us analyze each compound:
\(\text{H}_2\): Diatomic, nonpolar, symmetric. - Dipole moment = 0.
\(\text{CO}_2\): Linear molecule, symmetric. - Dipole moment = 0.
\(\text{BF}_3\): Planar triangular structure, symmetric. - Dipole moment = 0.
\(\text{CH}_4\): Tetrahedral geometry, symmetric. - Dipole moment = 0.
\(\text{SiF}_4\): Tetrahedral geometry, symmetric. - Dipole moment = 0.
\(\text{BeF}_2\): Linear molecule, symmetric. - Dipole moment = 0.
Molecules with nonzero dipole moments:
\(\text{HF}\): Polar molecule, asymmetric.
\(\text{H}_2\text{S}\): Bent structure, asymmetric.
\(\text{NH}_3\): Trigonal pyramidal structure, asymmetric.
\(\text{CHCl}_3\): Tetrahedral, but asymmetric due to \(\text{Cl}\).
\(\text{H}_2\text{O}\): Bent structure, asymmetric.
Conclusion: The compounds with zero dipole moment are:
\[\text{H}_2, \, \text{CO}_2, \, \text{BF}_3, \, \text{CH}_4, \, \text{SiF}_4, \, \text{BeF}_2.\]
The number of such compounds is:
\[6.\]
Final Answer: 6.