Answer :
To determine which formula represents a polar molecule, let's analyze the given molecules one by one:
1. Water (H₂O):
- Water is a polar molecule. It has a bent shape due to the two lone pairs on the oxygen atom. The difference in electronegativity between hydrogen and oxygen creates a dipole moment, making water a polar molecule.
2. Carbon Dioxide (CO₂):
- Carbon dioxide is a nonpolar molecule. It has a linear shape, and the two oxygen atoms are symmetrically aligned around the central carbon atom. Although the C=O bonds are polar, the dipoles cancel each other out due to the linear geometry, making CO₂ a nonpolar molecule.
3. Ammonia (NH₃):
- Ammonia is a polar molecule. It has a trigonal pyramidal shape due to the lone pair on the nitrogen atom. The difference in electronegativity between nitrogen and hydrogen creates a net dipole moment, making NH₃ a polar molecule.
4. Methane (CH₄):
- Methane is a nonpolar molecule. It has a tetrahedral shape with perfect symmetry. The hydrogen atoms are symmetrically distributed around the central carbon atom, and the dipole moments of the C-H bonds cancel out, making CH₄ a nonpolar molecule.
Based on this analysis, the molecule that represents a polar molecule is:
3. NH₃ (Ammonia)
Therefore, the correct answer is:
3. NH₃
1. Water (H₂O):
- Water is a polar molecule. It has a bent shape due to the two lone pairs on the oxygen atom. The difference in electronegativity between hydrogen and oxygen creates a dipole moment, making water a polar molecule.
2. Carbon Dioxide (CO₂):
- Carbon dioxide is a nonpolar molecule. It has a linear shape, and the two oxygen atoms are symmetrically aligned around the central carbon atom. Although the C=O bonds are polar, the dipoles cancel each other out due to the linear geometry, making CO₂ a nonpolar molecule.
3. Ammonia (NH₃):
- Ammonia is a polar molecule. It has a trigonal pyramidal shape due to the lone pair on the nitrogen atom. The difference in electronegativity between nitrogen and hydrogen creates a net dipole moment, making NH₃ a polar molecule.
4. Methane (CH₄):
- Methane is a nonpolar molecule. It has a tetrahedral shape with perfect symmetry. The hydrogen atoms are symmetrically distributed around the central carbon atom, and the dipole moments of the C-H bonds cancel out, making CH₄ a nonpolar molecule.
Based on this analysis, the molecule that represents a polar molecule is:
3. NH₃ (Ammonia)
Therefore, the correct answer is:
3. NH₃
NH
3
]
Explanation
1 Determine the molecular geometry of each compound to identify the polarity
2
[
O
2
]
[O
2
] is a diatomic molecule with a linear shape, making it nonpolar
3
[
C
O
2
]
[CO
2
] is a linear molecule with a symmetrical distribution of polar bonds, making it nonpolar overall
4
[
N
H
3
]
[NH
3
] has a trigonal pyramidal shape with a lone pair on nitrogen, making it a polar molecule
5
[
C
H
4
]
[CH
4
] is a tetrahedral molecule with symmetrical distribution of bonds, making it nonpolar
6 Therefore, the formula that represents a polar molecule is
[
N
H
3
]
[NH
3
]
3
]
Explanation
1 Determine the molecular geometry of each compound to identify the polarity
2
[
O
2
]
[O
2
] is a diatomic molecule with a linear shape, making it nonpolar
3
[
C
O
2
]
[CO
2
] is a linear molecule with a symmetrical distribution of polar bonds, making it nonpolar overall
4
[
N
H
3
]
[NH
3
] has a trigonal pyramidal shape with a lone pair on nitrogen, making it a polar molecule
5
[
C
H
4
]
[CH
4
] is a tetrahedral molecule with symmetrical distribution of bonds, making it nonpolar
6 Therefore, the formula that represents a polar molecule is
[
N
H
3
]
[NH
3
]
