Question

Which of the following is not a physical property of water? A) transparent B) colorless C) higher density in the liquid state than in the solid state D) changes to hydrogen and oxygen when electricity passes through it

Short answer

Option D is not a physical property of water.

Step-by-step solution

Understanding Physical Properties

Physical properties of a substance are characteristics that can be observed or measured without changing the substance's chemical identity. Examples include color, state (solid, liquid, gas), transparency, density, etc.

Analyze Option A

Option A states that water is transparent. This is a physical property because it describes how light passes through water without altering its chemical structure.

Evaluate Option B

Option B states that water is colorless. Being colorless is a physical property because it pertains to water's visual appearance without changing its chemical makeup.

Consider Option C

Option C indicates that water has a higher density in the liquid state than in the solid state. This is a unique physical property of water due to the structure of ice (solid water) being less dense than liquid water, leading to ice floating.

Examine Option D

Option D suggests water changes to hydrogen and oxygen when electricity passes through it. This process is known as electrolysis, which is a chemical change, not a physical property, as it results in a change in the chemical composition of water.

Key concepts

Transparency of Water

Water is known for its remarkable transparency, which means that it allows light to pass through it with little obstruction. This is an important physical property because it influences how we interact with and use water in our daily lives. For instance, the transparency of water is essential for aquatic life. Sunlight penetrates clear water, enabling photosynthesis in underwater plants and regulating temperatures.
Moreover, this property is vital for various human activities such as swimming, diving, and even determining the water's quality. When water is exceptionally clear, we often associate it with cleanliness and purity. However, just because water is transparent doesn't guarantee it's free of contaminants. It's crucial to understand that while transparency is a significant attribute, it doesn't tell the whole story about water quality.
Transparency in water arises because water molecules don't absorb visible light significantly. This allows light to travel through without scattering too much, which is why we can see through water and why it appears colorless to the naked eye.

Density of Water

The density of water is an intriguing and unique physical property. Unlike most substances, water has a greater density in its liquid state than in its solid state. This anomaly occurs due to the molecular structure of ice. When water freezes, it forms a crystalline structure that takes up more space, hence reducing its density compared to liquid water.
Because of this lower density, ice floats on water, a characteristic with significant environmental implications. For example, icebergs float in oceans, and during winter, ice forms a protective layer on lakes and bodies of water. This insulating layer helps maintain a stable temperature underneath, allowing aquatic life to survive in colder climates.
Overall, the density of water is measured as 1 g/cm³ at 4°C in its liquid state, making it an incredibly useful standard for various scientific calculations and applications. The behavior of water regarding density showcases its distinct nature and is pivotal in environmental and biological systems.

Electrolysis of Water

Electrolysis of water is a chemical process rather than a physical property. Through electrolysis, water is decomposed into hydrogen and oxygen gases when an electric current passes through it. This transformation occurs because the electric current provides the energy needed to break the bonds between hydrogen and oxygen atoms in the water molecule.
To conduct electrolysis, water needs to contain ions, typically achieved by adding a small amount of electrolyte, such as salt. Electrolysis is significant in various industrial processes, particularly in producing hydrogen, a clean energy source, and oxygen, which is essential for combustion and other processes.
This process demonstrates the transformation of water not only in its state but in its composition, providing an exciting insight into chemical reactions. Understanding electrolysis enhances our grasp of chemical properties and showcases water's potential beyond being a life-sustaining liquid. This capability highlights water's multifaceted nature beyond its commonly well-studied physical properties.