Certainly! Let's analyze each molecule in detail to determine its bond polarity, molecular geometry (shape), and overall molecular polarity.
### 1. HCl (Hydrochloric Acid)
- Bond Polarity: HCl has a polar bond. This is because chlorine (Cl) is more electronegative than hydrogen (H), resulting in an unequal sharing of electrons.
- Shape: The molecule HCl is linear. Since there are only two atoms, the molecule cannot have any angles and is thus linear.
- Molecular Polarity: HCl is a polar molecule. The polarity arises because the molecule is not symmetrical and has a permanent dipole moment from hydrogen to chlorine.
### 2. NH₃ (Ammonia)
- Bond Polarity: NH₃ has polar bonds. Nitrogen (N) is more electronegative than hydrogen (H), causing the bonds to be polar.
- Shape: The shape of NH₃ is trigonal pyramidal. This shape is due to the lone pair of electrons on the nitrogen atom, which causes a specific arrangement of the three hydrogen atoms around it.
- Molecular Polarity: NH₃ is a polar molecule. The trigonal pyramidal shape causes the dipoles from each N-H bond to add up vectorially, resulting in a net dipole moment for the molecule.
### 3. O₂ (Oxygen)
- Bond Polarity: O₂ has a nonpolar bond. This is because both oxygen atoms have the same electronegativity and share electrons equally.
- Shape: The shape of O₂ is linear. Since there are only two atoms, the molecular shape must be linear.
- Molecular Polarity: O₂ is a nonpolar molecule. The molecule is symmetric with no difference in electronegativity between the two atoms, leading to no permanent dipole moment.
### 4. C₂H₂ (Acetylene)
- Bond Polarity: C₂H₂ has polar C-H bonds. Carbon (C) is more electronegative than hydrogen (H), making these bonds polar.
- Shape: The shape of C₂H₂ is linear. Acetylene features a triple bond between the two carbon atoms and each carbon is bonded to one hydrogen atom, which aligns all the atoms in a straight line.
- Molecular Polarity: C₂H₂ is a nonpolar molecule. Despite having polar C-H bonds, the linear symmetry of the molecule causes the dipoles to cancel out, resulting in an overall nonpolar molecule.
In summary, HCl and NH₃ are polar molecules due to their bond polarity and molecular shapes leading to a net dipole moment. On the other hand, O₂ and C₂H₂ are nonpolar molecules because their respective bond polarities and molecular shapes result in no net dipole moment.
