本题目来源于试卷: Models of Bonding & Structure B.2 The Covalent Model，类别为 IB化学
[单选题]
Which molecule would be considered polar covalent?
A. $CO_2$
B. $NH_3$
C. $CH_4$
D. $SO_3$
参考答案: B
本题详细解析:
The bonds between N and H are polar due to the difference in electronegativity.
The overall shape of the NH3 is asymmetrical (trigonal pyramidal), resulting in a molecule with a net dipole moment. $CO_2$ and $SO_3$ both have polar bonds, but the molecules are symmetrical. Therefore, they do not have net dipole moment.
The C-H bonds are not polar due to a small difference in electronegativity.
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