Which compound contains only a nonpolar covalent molecule?
$O _2$
HCl
$H _2 O$
$NO _3$
Answer (2)
Nonpolar covalent molecules form when electrons are shared equally between atoms.
O 2 consists of two identical oxygen atoms, resulting in a zero electronegativity difference and a nonpolar covalent bond.
HCl, H 2 O , and N O 3 have significant electronegativity differences between their atoms, making their bonds polar covalent.
Therefore, the compound containing only a nonpolar covalent molecule is O 2 .
Explanation
Understanding Nonpolar Covalent Molecules We are asked to identify which of the given compounds contains only a nonpolar covalent molecule. A nonpolar covalent molecule is formed when electrons are shared equally between atoms, which occurs when the electronegativity difference between the atoms is zero or very small.
Analyzing Each Compound Let's analyze each compound:
O 2 : This molecule consists of two oxygen atoms. Since both atoms are the same, the electronegativity difference is zero. Therefore, the bond is nonpolar covalent.
HCl : This molecule consists of hydrogen and chlorine atoms. There is a significant electronegativity difference between hydrogen and chlorine, making the bond polar covalent.
H 2 O : This molecule consists of hydrogen and oxygen atoms. There is a significant electronegativity difference between hydrogen and oxygen, making the bonds polar covalent.
N O 3 : This is the nitrate ion. Nitrogen and oxygen have a significant electronegativity difference, so the bonds are polar covalent.
Conclusion Based on the analysis, only O 2 contains a nonpolar covalent bond because the electronegativity difference between the two oxygen atoms is zero.
Examples
Nonpolar covalent molecules are crucial in various real-world applications. For instance, the air we breathe, primarily composed of nitrogen ( N 2 ) and oxygen ( O 2 ), relies on nonpolar covalent bonds. These bonds ensure that the gases remain stable and do not readily react with each other under normal conditions. Similarly, many organic compounds, such as fats and oils, contain carbon-carbon and carbon-hydrogen bonds, which are essentially nonpolar. This property allows these compounds to mix with each other but not with water, a principle utilized in cooking and industrial processes.
The compound that contains only a nonpolar covalent molecule is O 2 because it consists of two identical oxygen atoms that share electrons equally. The other compounds (HCl, H 2 O , and N O 3 ) have polar covalent bonds due to significant electronegativity differences between their atoms.
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