Answer :

To determine which bond is characterized by the equal sharing of electrons, we need to consider the concept of electronegativity. Electronegativity is a measure of how strongly an atom attracts shared electrons in a chemical bond. When two atoms form a bond, the difference in their electronegativities determines the type of bond:

1. A non-polar covalent bond occurs when the electronegativity difference between the two atoms is very small or none, leading to an equal sharing of electrons.

2. A polar covalent bond occurs when there is a moderate difference in electronegativity, resulting in unequal sharing of electrons.

3. An ionic bond occurs when there is a large difference in electronegativity, causing one atom to completely transfer an electron to the other.

Let’s analyze each option:

a) H-Cl (Hydrogen-Chlorine):
- Hydrogen has an electronegativity of approximately 2.1.
- Chlorine has an electronegativity of approximately 3.0.
- The difference between Hydrogen and Chlorine is about 0.9, which is significant. This creates a polar covalent bond with unequal sharing of electrons.

b) C-H (Carbon-Hydrogen):
- Carbon has an electronegativity of approximately 2.5.
- Hydrogen has an electronegativity of approximately 2.1.
- The difference between Carbon and Hydrogen is just 0.4, which is quite small. This leads to a non-polar covalent bond characterized by equal sharing of electrons.

c) O-H (Oxygen-Hydrogen):
- Oxygen has an electronegativity of approximately 3.5.
- Hydrogen has an electronegativity of approximately 2.1.
- The difference between Oxygen and Hydrogen is about 1.4, which is significant. This creates a polar covalent bond with unequal sharing of electrons.

d) N-H (Nitrogen-Hydrogen):
- Nitrogen has an electronegativity of approximately 3.0.
- Hydrogen has an electronegativity of approximately 2.1.
- The difference between Nitrogen and Hydrogen is about 0.9, which is significant. This creates a polar covalent bond with unequal sharing of electrons.

From this analysis, the bond that is characterized by the equal sharing of electrons is the C-H bond. Therefore, the correct answer is:

b) C-H