Methylene chloride (dichloromethane, CH2Cl2) was once a common ingredient in many paint strippers. Based on its molecular formula, what kind of bonding does this compound exhibit? A) Ionic only B) Covalent only C) Both ionic and covalent D) Metallic only
The Correct Answer and Explanation is:
Correct Answer: B) Covalent only
Explanation:
Methylene chloride, also known as dichloromethane, has the molecular formula CH₂Cl₂, indicating it contains one carbon (C) atom, two hydrogen (H) atoms, and two chlorine (Cl) atoms. To understand the type of bonding in this molecule, we need to look at the electronegativity and the nature of the elements involved.
1. Nature of the Elements:
- Carbon, hydrogen, and chlorine are all nonmetals.
- Ionic bonds generally form between metals and nonmetals, where electrons are transferred from one atom (typically a metal) to another (typically a nonmetal).
- Covalent bonds, on the other hand, form between nonmetals, where electrons are shared between atoms.
2. Bonding in CH₂Cl₂:
- In methylene chloride, the carbon atom serves as the central atom and forms four single covalent bonds:
- Two with hydrogen atoms
- Two with chlorine atoms
Each bond in CH₂Cl₂ involves shared pairs of electrons, which is the hallmark of covalent bonding. Although chlorine is more electronegative than carbon and hydrogen, it does not pull the electrons away completely to form ions; instead, it creates polar covalent bonds with partial charges due to unequal electron sharing.
3. Why Not Ionic, Metallic, or Both?
- There are no metal atoms in CH₂Cl₂, so metallic bonding is not possible.
- There is no complete electron transfer (as seen in ionic bonds), so ionic bonding does not occur.
- The molecule is held together entirely by covalent bonds, though some are polar due to differences in electronegativity.
Conclusion:
Methylene chloride (CH₂Cl₂) exhibits covalent bonding only, specifically polar covalent bonds between the carbon and chlorine atoms, and nonpolar covalent bonds between carbon and hydrogen atoms. Therefore, the correct answer is B) Covalent only.