Among the following, a pair of a compound and an element respectively is

Options

A. iron powder and rust powder.
B. rust powder and iron powder.
C. lime and rust powder.
D. rust powder and lime.

Explanation

To solve the question, we need to identify a pair consisting of one compound and one element from the given options. Let's break down the solution step by step.

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Element**: A pure substance that cannot be broken down into simpler substances by chemical means. Elements consist of only one type of atom.
- **Compound**: A substance formed when two or more different elements chemically bond together in a fixed ratio. Compounds have different properties from the elements that form them.

2. **Analyze the Given Options**:
- **Iron Powder (Fe)**: This is an element because it consists of only iron atoms.
- **Rust Powder (Iron Oxide, FeO)**: This is a compound because it consists of iron (Fe) and oxygen (O) atoms bonded together.
- **Lime (Ca(OH)₂)**: This is also a compound because it is made of calcium (Ca), oxygen (O), and hydrogen (H) atoms bonded together.

3. **Identify the Pair**:
- From the analysis, we see that Iron Powder (Fe) is an element, and Rust Powder (FeO) is a compound. Therefore, the pair of a compound and an element is:
- **Element**: Iron Powder (Fe)
- **Compound**: Rust Powder (FeO)

4. **Conclusion**:
- The correct answer is the pair of Iron Powder (Fe) as the element and Rust Powder (FeO) as the compound.

### Final Answer:
The pair of a compound and an element respectively is Iron Powder (Fe) and Rust Powder (FeO).

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