What happens to particles of ammonium chloride when it undergoes sublimation?

Options

A. Particles gain energy, move faster, come closer and change to liquid state.
B. Particles gain energy, move faster, come closer and change to gaseous state.
C. Particles gain energy, move faster, go away from each other and change to gaseous state.
D. Particles lose energy and move far away from each other to change into gaseous state.

Explanation

To understand what happens to the particles of ammonium chloride (NH4Cl) when it undergoes sublimation, let's break down the process step by step:

### Step 1: Understanding Sublimation
- Sublimation is the process where a solid changes directly into a gas without passing through the liquid state.

### Step 2: Heating Ammonium Chloride
- When ammonium chloride is heated, the particles of the solid gain energy. This energy comes from the heat applied to the substance.

### Step 3: Energy Gain and Particle Movement
- As the particles gain energy, they begin to vibrate more rapidly. This increase in energy causes the particles to move faster.

### Step 4: Decrease in Intermolecular Forces
- With the increase in speed and energy, the intermolecular forces that hold the particles together in the solid state weaken. This is because the particles are vibrating so quickly that they can overcome the attractive forces that keep them close together.

### Step 5: Transition to Gaseous State
- As the intermolecular forces weaken, the particles begin to move apart from each other. Eventually, they break free from the solid structure and enter the gaseous state. In the gaseous state, the particles are much farther apart compared to their arrangement in the solid state.

### Conclusion
- Therefore, when ammonium chloride undergoes sublimation, the particles gain energy, move faster, and move away from each other, transitioning into the gaseous state.

### Final Answer
The correct option is: **Particles gain energy, move faster, go away from each other and change to gaseous state.**

---