To determine which of the following molecules represents a molecule characterized by polar covalent bonding, let's analyze each option based on the nature of the bonds within the molecule:
a) [tex]\(H_2\)[/tex]:
- [tex]\(H_2\)[/tex] is a molecule consisting of two hydrogen atoms. Since both atoms are identical, they have the same electronegativity. Therefore, the bond between the two hydrogen atoms is a nonpolar covalent bond.
b) [tex]\(CH_4\)[/tex]:
- [tex]\(CH_4\)[/tex] is methane, a compound consisting of one carbon atom bonded to four hydrogen atoms. The difference in electronegativity between carbon (C) and hydrogen (H) is relatively small. Thus, the C-H bonds are considered nonpolar covalent bonds.
c) [tex]\(H_2O\)[/tex]:
- Water, [tex]\(H_2O\)[/tex], consists of two hydrogen atoms bonded to an oxygen atom. Oxygen is significantly more electronegative than hydrogen, leading to an uneven distribution of electron density. As a result, the H-O bonds are polar covalent bonds, indicating that the molecule has regions of partial positive and negative charges.
d) [tex]\(C - C\)[/tex]:
- A [tex]\(C - C\)[/tex] bond, as seen in ethane ([tex]\(C_2H_6\)[/tex]) or any molecule with a carbon-carbon single bond, involves two carbon atoms of the same element. Since the two atoms are identical, they share electrons equally, forming a nonpolar covalent bond.
e) [tex]\(NaCl\)[/tex]:
- Sodium chloride ([tex]\(NaCl\)[/tex]) is composed of sodium (Na), a metal, and chlorine (Cl), a non-metal. This combination forms an ionic bond due to the large difference in electronegativity between the two atoms, resulting in the transfer of electrons from sodium to chlorine.
Based on the analysis above, the molecule characterized by polar covalent bonding is:
[tex]\[ \boxed{c) \, H_2O} \][/tex]
