To determine which molecule exhibits dipole-dipole attraction between molecules, we need to consider the molecular geometry and the electronegativity differences between the atoms in each molecule. Dipole-dipole forces occur between polar molecules, which have a net dipole moment due to an uneven distribution of electron density.
1. AsH[tex]\(_3\)[/tex] (Arsine):
- Arsenic (As) is less electronegative than hydrogen (H).
- The molecule has a trigonal pyramidal shape due to the lone pair on the As atom.
- This shape and the difference in electronegativity create a net dipole moment.
- Hence, AsH[tex]\(_3\)[/tex] is a polar molecule and exhibits dipole-dipole attraction.
2. BH[tex]\(_3\)[/tex] (Boron trihydride):
- Boron (B) is less electronegative than hydrogen (H), but not significantly.
- The molecule has a trigonal planar shape.
- The structure is symmetrical, and any dipoles cancel out.
- Therefore, BH[tex]\(_3\)[/tex] is nonpolar and does not exhibit dipole-dipole attraction.
3. F[tex]\(_2\)[/tex] (Fluorine gas):
- Consists of two fluorine (F) atoms with equal electronegativity.
- Forms a nonpolar covalent bond because of the identical atoms.
- F[tex]\(_2\)[/tex] is nonpolar and does not exhibit dipole-dipole attraction.
4. SiS[tex]\(_2\)[/tex] (Silicon disulfide):
- Silicon (Si) is less electronegative than sulfur (S).
- The molecule is linear with a symmetrical arrangement.
- The dipoles cancel out due to this symmetry.
- Therefore, SiS[tex]\(_2\)[/tex] is nonpolar and does not exhibit dipole-dipole attraction.
5. CCl[tex]\(_4\)[/tex] (Carbon tetrachloride):
- Carbon (C) is less electronegative than chlorine (Cl).
- The molecule has a tetrahedral shape, which is symmetrical.
- The symmetrical shape causes the dipoles to cancel each other out.
- Thus, CCl[tex]\(_4\)[/tex] is nonpolar and does not exhibit dipole-dipole attraction.
Having considered the geometries and electronegativities, we find that only AsH[tex]\(_3\)[/tex] exhibits dipole-dipole attraction due to its polar nature. Therefore, the correct answer is:
AsH[tex]\(_3\)[/tex]
