Understanding Matter and Potassium Permanganate Dissolving in Water

The question describes a common experiment where a crystal of potassium permanganate is placed in water, and the water gradually turns pink. This observation tells us something fundamental about the nature of matter.

What Happens When Potassium Permanganate Dissolves?

Potassium permanganate is a solid substance made up of tiny particles. Water is a liquid, also made up of tiny particles. When the solid potassium permanganate crystal is placed in water, its particles begin to break away from the crystal and spread out throughout the water.

This spreading out of particles from a region of higher concentration (the crystal) to a region of lower concentration (the rest of the water) is called diffusion. The water turns pink because the individual particles of potassium permanganate are colored and they mix with the water particles.

Connecting the Observation to Characteristics of Matter

The fact that the potassium permanganate particles can move and spread out within the water indicates that there must be 'room' for them to move into. This 'room' is the space that exists between the particles of water.

If water particles were packed tightly together with no space between them, the potassium permanganate particles would not be able to move through the water and spread evenly, causing the whole beaker of water to turn pink over time.

Analysing the Options

Let's look at the given options in the context of this observation:

• Option 1: Particles of solids break easily when pressure is applied on them.
  This characteristic might be true for some solids, but the observation is about dissolving and mixing, not about applying pressure to break the crystal. It doesn't explain why the pink color spreads throughout the water.
• Option 2: Particles of matter have space in between them.
  This aligns with our observation. The potassium permanganate particles spread throughout the water by moving into the spaces between the water particles. This explains why the pink color eventually becomes uniform.
• Option 3: Particles of solids are tightly bound and they are rigid.
  While particles in a solid are generally tightly bound and contribute to rigidity, this option describes the solid itself, not how it interacts when dissolving in a liquid. The observation focuses on the spreading of particles within the liquid, which relies on the nature of the liquid and the ability of the solid's particles to separate and move.
• Option 4: Particles of liquid are loosely bound and they can flow.
  This option correctly describes a characteristic of liquids (like water), which allows them to flow. However, the crucial part of the observation is not just that water flows, but that the solute (potassium permanganate) can mix with the water. This mixing relies on the spaces within the liquid structure, which is a more direct inference from the spreading color than just the ability of the liquid to flow. The spreading confirms there are spaces for particles to occupy.

Based on the detailed analysis of the experiment and how the pink color spreads, the most direct characteristic of matter inferred is that particles of matter have space between them. This space allows for diffusion to occur, leading to the uniform distribution of potassium permanganate particles throughout the water.