Which compound contains only a nonpolar covalent molecule?
$O _2$
HCl
$H _2 O$
$NO _3$
Answer (2)
The compound that contains only a nonpolar covalent molecule is O 2 .
Explanation
Understanding the Problem We are asked to identify the compound that contains only a nonpolar covalent molecule from the given options: O 2 , HCl, H 2 O , N O 3 . A nonpolar covalent bond occurs when electrons are shared equally between atoms. A polar covalent bond occurs when electrons are shared unequally between atoms, resulting in a dipole moment. The electronegativity difference between atoms determines the polarity of a bond. Molecules with only nonpolar bonds are nonpolar molecules. Molecules with polar bonds can be polar or nonpolar depending on their geometry and the cancellation of dipole moments.
Analyzing O 2 For O 2 , the bond is between two oxygen atoms, which have the same electronegativity. Therefore, the bond is nonpolar covalent, and the molecule is nonpolar.
Analyzing HCl For HCl, the bond is between hydrogen and chlorine, which have different electronegativities. Therefore, the bond is polar covalent, and the molecule is polar.
Analyzing H 2 O For H 2 O , the bonds are between hydrogen and oxygen, which have different electronegativities. The molecule has a bent shape, so the dipole moments do not cancel, and the molecule is polar.
Analyzing N O 3 For N O 3 , the bonds are between nitrogen and oxygen, which have different electronegativities. The nitrate ion has a trigonal planar geometry, and the formal charges are distributed such that there is resonance. The N O 3 − ion is polar.
Conclusion Based on the analysis, the compound with only nonpolar covalent bonds is O 2 .
Examples
Nonpolar covalent molecules are crucial in various applications, such as creating hydrophobic coatings. For example, the water-repellent properties of certain fabrics are achieved by coating them with nonpolar substances. These substances prevent water molecules from adhering to the fabric, keeping it dry. Understanding nonpolar molecules helps in designing materials with specific properties, like resistance to water or other polar solvents.
The compound that contains only a nonpolar covalent molecule is O 2 , as it consists of two identical oxygen atoms that share electrons equally. In contrast, HCl, H 2 O , and N O 3 − have polar covalent bonds due to differing electronegativities. Therefore, O 2 is the correct choice.
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