Question

which one of the following molecules has dipole - dipole forces as its strongest intermolecular force?
a. $ch_3nh_2$
b. $h_2o$
c. $nacl$
d. $h_2s$
e. $xecl_2$

Explanation:

• For \(CH_3NH_2\): It has hydrogen - bonding (stronger than dipole - dipole forces) due to \(N - H\) bonds.
• For \(H_2O\): It has hydrogen - bonding (stronger than dipole - dipole forces) due to \(O - H\) bonds.
• For \(NaCl\): It has ionic bonds (stronger than dipole - dipole forces).
• For \(H_2S\): It has dipole - dipole forces as its strongest intermolecular force. \(S\) is less electronegative than \(O\) and \(N\), so no hydrogen - bonding. It is a polar molecule (\(H - S\) bonds with a bent geometry), so dipole - dipole forces are present and are the strongest intermolecular forces.
• For \(XeCl_2\): It is a non - polar molecule (linear geometry, symmetric distribution of electron density around \(Xe\)), so London dispersion forces are the strongest intermolecular forces.

Answer:

D. \(H_2S\)