When a solute(here solid ) is adsorbed from a solution is called Positive adsorption vice versa when a solvent is adsorbed it is called negative adsorption.

Answer:

Introduction:
The adsorption of solids from a solution refers to the process of the accumulation of a substance (the adsorbate) onto the surface of a solid (the adsorbent) from a solution. This process can be classified into two types: physical adsorption and chemical adsorption. The correct answer to the given question is option 'D', positive adsorption.

Physical Adsorption:
Physical adsorption, also known as physisorption or van der Waals adsorption, is a type of adsorption in which the adsorbate molecules are attracted to the surface of the adsorbent through weak van der Waals forces. These forces include London dispersion forces, dipole-dipole interactions, and hydrogen bonding. Physical adsorption is a reversible process and occurs at relatively low temperatures. The adsorption is usually non-specific and does not involve any chemical reactions between the adsorbate and adsorbent.

Chemical Adsorption:
Chemical adsorption, also known as chemisorption, is a type of adsorption in which the adsorbate molecules form chemical bonds with the surface of the adsorbent. Unlike physical adsorption, chemical adsorption involves the breaking and formation of chemical bonds. This process is usually irreversible and occurs at higher temperatures compared to physical adsorption. Chemical adsorption is often highly specific and involves specific interactions between the adsorbate and adsorbent.

Negative and Positive Adsorption:
The terms "negative adsorption" and "positive adsorption" are not commonly used in the context of adsorption. It is possible that these terms are used in a specific context or by a particular author, but they are not widely recognized or accepted in the field of adsorption.

However, if we assume that "negative adsorption" refers to the absence or reduction of adsorption, and "positive adsorption" refers to the presence or increase in adsorption, then the correct answer to the given question would be option 'D', positive adsorption. This would imply that the adsorption of solids from a solution is generally considered to be a positive phenomenon, as it involves the accumulation of the adsorbate onto the surface of the adsorbent.