Question

A change in which intrinsic property of water would MOST affect its polarity? A. Atomic electronegativity B. Chirality C. Intermolecular forces D. Solubility

Short answer

A. Atomic electronegativity

Step-by-step solution

- Understand the Question

Determine what the question is asking. In this case, identify which intrinsic property of water would have the greatest impact on its polarity.

- Define Polarity

Polarity in a molecule arises from the distribution of electric charges between its atoms. This distribution depends on differences in atomic electronegativity and the shape of the molecule.

- Assess Property A - Atomic Electronegativity

Atomic electronegativity is the ability of an atom to attract electrons. For water, this means the oxygen atom attracts electrons more strongly than the hydrogen atoms, creating a dipole moment.

- Assess Property B - Chirality

Chirality refers to the geometric property where a molecule is not superimposable on its mirror image. Water is not a chiral molecule, so this property does not affect its polarity.

- Assess Property C - Intermolecular Forces

Intermolecular forces such as hydrogen bonding affect the interactions between water molecules but do not directly affect the intrinsic polarity of the water molecule itself.

- Assess Property D - Solubility

Solubility is the ability of a substance to dissolve in another substance. While water's polarity impacts its solubility with other polar substances, changing solubility does not necessarily change the intrinsic polarity.

- Conclusion

Determine that atomic electronegativity has the most significant impact on the intrinsic polarity of water as it directly affects how electrons are distributed within the molecule.

Key concepts

Atomic Electronegativity

Atomic electronegativity is a key concept to understand when discussing the polarity of water. Electronegativity refers to an atom's ability to attract and hold onto electrons. In the case of water, the oxygen atom is significantly more electronegative than the hydrogen atoms. This difference creates a scenario where the shared electrons spend more time closer to the oxygen atom compared to the hydrogen atoms.

This uneven distribution of electrons results in a partial negative charge near the oxygen atom and partial positive charges near the hydrogen atoms. This separation of charge within the molecule is what we call a dipole moment. The dipole moment is directly responsible for the polarity of water.
The strong electronegativity of oxygen is thus crucial for establishing the structure and behavior of water molecules. Without this property, water would not exhibit the same polar characteristics it is known for.

Molecular Polarity

Molecular polarity is a broader term that describes the distribution of electrical charges across a molecule. A molecule is considered polar when it has a significant dipole moment, like water. For water, molecular polarity stems from both its atomic constituents and its bent molecular shape.

Due to the angular (bent) structure of the water molecule, the polar bonds between oxygen and hydrogen do not cancel each other out. Instead, they create an overall dipole moment with a positive and a negative side. This makes water a polar molecule.
Molecular polarity is important because it influences various properties like solubility, boiling and melting points, and interactions with other molecules. For instance, the polar nature of water allows it to dissolve many other polar substances, making it an excellent solvent.
The unique combination of high electronegativity of oxygen and the bent molecular shape ensures that water has a strong dipole moment and thus exhibits significant molecular polarity.

Intrinsic Properties of Water

Water has several intrinsic properties that make it unique and vital for life. Among these, its polarity is one of the most significant. Water's polarity comes from the differences in atomic electronegativity between oxygen and hydrogen and its molecular geometry.

Being a polar molecule, water exhibits strong hydrogen bonding, which is an attraction between the hydrogen atom of one water molecule and the oxygen atom of another. These hydrogen bonds are responsible for many of water's unique properties, such as high specific heat, surface tension, and cohesive and adhesive behaviors.

• **High Specific Heat**: Water can absorb a lot of heat before its temperature rises, which helps regulate climate and body temperature.
• **Surface Tension**: The hydrogen bonds between water molecules give water a high surface tension. This allows small insects to walk on water and drops to form.
• **Cohesion and Adhesion**: Water molecules stick to each other (cohesion) and to other surfaces (adhesion), facilitating processes like transpiration in plants.

Understanding these intrinsic properties reveals how crucial atomic electronegativity and molecular polarity are to the behavior and roles of water in the natural world.