Catalytic converters are used in

Options

A. automobiles
B. wind mills
C. poultry farms
D. diary farms.

Explanation

### Step-by-Step Solution:

1. **Understanding Catalytic Converters**:
- Catalytic converters are devices used in vehicles to reduce harmful emissions. They facilitate a chemical reaction that transforms toxic gases into less harmful substances.

**Hint**: Think about how vehicles emit gases and the need to reduce their toxicity.

2. **Function of Catalytic Converters**:
- They primarily work through redox (reduction-oxidation) reactions. This means they help in both reducing harmful substances and oxidizing others to convert them into less harmful forms.

**Hint**: Remember that redox reactions involve both gaining and losing electrons, which changes the substances involved.

3. **Types of Gases Treated**:
- The main gases that catalytic converters target include hydrocarbons (unburned fuel), carbon monoxide (a toxic gas), and nitrogen oxides.

**Hint**: Focus on the types of emissions that are harmful and need to be converted.

4. **Products of the Reaction**:
- The conversion process results in the production of carbon dioxide and water, which are significantly less harmful to the environment.

**Hint**: Consider what happens to the harmful gases after they pass through the catalytic converter.

5. **Materials Used in Catalytic Converters**:
- Common materials used in catalytic converters include precious metals like platinum, palladium, and rhodium, which act as catalysts to speed up the reactions.

**Hint**: Think about why certain metals are chosen for their catalytic properties.

6. **Applications**:
- Catalytic converters are primarily used in automobiles, including cars and motorcycles, to minimize air pollution from exhaust emissions.

**Hint**: Identify the main context where these devices are essential for reducing pollution.

### Final Answer:
Catalytic converters are used in **automobiles** such as cars and motorcycles to reduce harmful emissions by converting toxic gases into less harmful substances.