Questions: Which formula represents a polar molecule containing polar covalent bonds?

Solution Steps

A polar molecule is one that has a net dipole moment due to the presence of polar covalent bonds and an asymmetrical shape. A polar covalent bond occurs when two atoms with different electronegativities share electrons unequally, resulting in a partial positive charge on one atom and a partial negative charge on the other.

• Option a) $\mathrm{CH}_{4}$: Methane ($\mathrm{CH}_{4}$) has polar covalent bonds between carbon and hydrogen, but the molecule is symmetrical, resulting in no net dipole moment. Therefore, it is nonpolar.

• Option b) $F_{2}$: Fluorine ($F_{2}$) is a diatomic molecule with a nonpolar covalent bond because the two atoms have the same electronegativity, resulting in no dipole moment.

• Option c) $\mathrm{NH}_{3}$: Ammonia ($\mathrm{NH}_{3}$) has polar covalent bonds between nitrogen and hydrogen. The molecule is asymmetrical (trigonal pyramidal shape), resulting in a net dipole moment. Therefore, it is a polar molecule.

• Option d) NaCl: Sodium chloride (NaCl) is an ionic compound, not a molecule with covalent bonds. It consists of ionic bonds between sodium and chloride ions.

Final Answer