The diffusion of a solid in another solid is a very slow process because the particles in solids can not move from their positions.the particles can show a little vibrations about their fixed position.due to lack of sufficient movements in particles of solids,the diffusion of solids in solids is a slow process.

It means that Other than solids, we can see diffusion in liquids n gases more likely......

Introduction:

In the study of diffusion, it is important to understand the different states of matter and how particles move within them. Diffusion refers to the process by which particles move from an area of higher concentration to an area of lower concentration. While diffusion is commonly associated with gases and liquids, it also occurs in solids although at a much slower rate. The National Council of Educational Research and Training (NCERT) states that "diffusion in solids" is more likely than "diffusion of solids." Let's delve into the reasons behind this statement.

Explanation:

1. Definition of Diffusion:
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. It is a result of the random motion of particles.

2. Diffusion in Gases and Liquids:
In gases and liquids, diffusion occurs more rapidly due to the higher mobility of particles. The particles in these states of matter have more freedom to move and collide with one another, allowing for faster diffusion.

3. Diffusion in Solids:
In solids, diffusion also takes place, but at a much slower rate. The movement of particles in solids is more restricted compared to gases and liquids. The particles in solids vibrate in fixed positions and have limited space to move around. As a result, the diffusion process in solids is significantly slower.

4. Atomic Arrangement in Solids:
The arrangement of atoms in solids plays a crucial role in determining the rate of diffusion. In most solids, the atoms are closely packed and held together by strong interatomic forces. This arrangement restricts the movement of atoms, making diffusion in solids more difficult.

5. Types of Diffusion in Solids:
Diffusion in solids can occur through two main mechanisms:

- Interstitial Diffusion: This type of diffusion involves the movement of smaller atoms or ions through the spaces between the larger atoms in a solid crystal lattice. Interstitial diffusion is generally slower than other forms of diffusion.

- Substitutional Diffusion: Substitutional diffusion occurs when atoms of one type replace atoms of another type within the crystal lattice. This type of diffusion is also relatively slow due to the strong forces holding the atoms in place.

Conclusion:

In conclusion, the statement made by NCERT, stating that "diffusion in solids rather than of solids is more likely," is based on the understanding that diffusion in solids occurs at a much slower rate compared to gases and liquids. The restricted movement of particles in solids due to their closely packed arrangement and strong interatomic forces hinders the diffusion process. While diffusion in solids is possible, it is important to recognize the significant difference in speed compared to other states of matter.