Mists are produced by

Options

A. smoke formed during combustion of organic matter
B. particles of spray liquids and by condensation of vapours in air
C. fine solid particles produced during crushing and grinding
D. condensation of vapurs during chemical reactions

Explanation

To solve the question "Mists are produced by," we need to understand what mist is and how it forms. Here’s a step-by-step breakdown of the solution:

### Step 1: Define Mist
Mist is defined as a suspension of tiny liquid droplets in the air. It is similar to fog but typically less dense.

**Hint:** Remember that mist consists of liquid droplets, not solid particles or gases.

### Step 2: Identify the Formation Processes
Mists can be produced through two primary processes:
1. **Condensation of vapor in the air:** This occurs when water vapor cools and condenses into tiny droplets.
2. **Spraying of liquid:** This involves the mechanical dispersion of liquid into small droplets.

**Hint:** Think about how water vapor behaves when it cools down or when liquids are sprayed.

### Step 3: Analyze the Options
Now, let's evaluate the given options:

- **Option A:** Smoke formed during the combustion of organic compounds. This is primarily composed of gases and solid particles, not liquid droplets. **(Incorrect)**

- **Option B:** Particles of spray liquid and condensation of vapor in the air. This option correctly describes the formation of mist as it includes both processes that lead to the creation of liquid droplets. **(Correct)**

- **Option C:** Fine solid particles produced during crushing and grinding. This describes dust, not mist, as it refers to solid particles. **(Incorrect)**

- **Option D:** Condensation of vapor during a chemical reaction. While condensation can produce mist, the phrasing suggests that it is only due to chemical reactions, which is misleading. **(Incorrect)**

### Step 4: Conclusion
Based on the analysis, the correct answer is **Option B**, which states that mists are produced by particles of spray liquid and by condensation of vapor in the air.

**Final Answer:** Mists are produced by particles of spray liquid and condensation of vapor in the air.