Question

Adsorption due to strong chemical forces is called : (a) Chemisorption (b) Physisorption (c) Both (a) and (b) (d) None of these

Short answer

The correct answer is (a) Chemisorption.

Step-by-step solution

Understand the Types of Adsorption

Adsorption can occur mainly through two different processes: physisorption, which is due to weak van der Waals forces, and chemisorption, which involves a stronger chemical bond between the adsorbate and the surface of the material.

Identify the Correct Option

The question specifically asks for the type of adsorption that occurs due to strong chemical forces. This directly refers to chemisorption.

Choose the Correct Answer

Since chemisorption is characterized by the formation of a strong chemical bond, the correct answer must refer to this process. Therefore, option (a) Chemisorption is the correct choice.

Key concepts

Adsorption

Adsorption is a surface phenomenon where particles, such as atoms, ions, or molecules from a gas, liquid, or dissolved solid adhere to a surface. This adhesion happens as the particles seek to minimize their surface energy by attaching to a solid material. Adsorption is widely used in various industries, for instance in air filters, where it helps to cleanse air by removing contaminants.

In educational problems, understanding adsorption is key for grasping how materials interact at the molecular level. Recognizing adsorption and its applications can have a profound impact on design, manufacturing, and environmental technology, as well as in the development of medical products and air and water purification systems.

Physisorption

Physisorption denotes the type of adsorption process where the adsorbate adheres to the surface of a material through weak van der Waals forces. These interactions are non-covalent and result from fluctuations in the electron distribution within molecules or atoms leading to temporary dipoles.

As such, the energy involved in physisorption is relatively low in comparison to chemical bonds. It's also reversible and can occur at low temperatures. Physisorption phenomena are critical in various scientific fields, like in the creation of sensors or the development of new materials with highly specific surface properties.

Van der Waals Forces

Van der Waals forces, named after Dutch scientist Johannes Diderik van der Waals, are the weak forces of attraction between molecules or atoms. These subatomic forces fall off rapidly with increasing distance between interacting particles. They are significant in physisorption processes, often governing how molecules form clusters or condense from gases to liquids at low temperatures.

Understanding van der Waals forces is crucial for comprehending the behavior of gases, the properties of liquids, and the structural integrity of molecular crystals. Students studying chemistry are often required to take these forces into account when predicting molecular interactions and stability.

Chemical Bonds

Chemical bonds are the strong connections between atoms or ions that hold molecules and compounds together. They are the backbone of chemical structure and reactivity, coming in various types such as covalent, ionic, metallic, and hydrogen bonds.

Chemisorption involves the formation of such chemical bonds and is generally stronger and more specific than physisorption, leading to changes in the electronic structure of the adsorbate and the surface. This concept is essential for students to learn as it underpins much of chemistry and materials science, elucidating how substances combine and interact on a molecular level.