In the metallurgical extraction of copper, following reaction is used:
`FeO+SiO_2 rarr FeSiO_3`
`FeO` and `FeSiO_3` respectively are.

Options

A. gangue and flux.
B. flux and slag
C. slag and flux.
D. gangue and slag

Explanation

To solve the question regarding the metallurgical extraction of copper and the reaction given, we need to analyze the components involved in the reaction:

1. **Identify the Reactants and Products:**
The reaction provided is:
\[ \text{FeO} + \text{SiO}_2 \rightarrow \text{FeSiO}_3 \]
Here, FeO (iron(II) oxide) and SiO2 (silicon dioxide) are the reactants, while FeSiO3 (iron(II) silicate) is the product.

2. **Classify the Components:**
- **FeO (Iron(II) oxide)**: This is typically considered as the gangue material in the extraction of metals. Gangue is the term used for the unwanted material that is separated from the ore during the extraction process.
- **SiO2 (Silicon dioxide)**: This acts as a flux in the metallurgical process. A flux is a substance that is added to the ore to help in the melting process and to combine with impurities to form a slag.
- **FeSiO3 (Iron(II) silicate)**: This is the slag formed from the reaction of FeO and SiO2. Slag is the byproduct that is removed from the furnace during the extraction of metals.

3. **Conclusion:**
Based on the classifications:
- FeO is the gangue.
- FeSiO3 is the slag.

Thus, the answer to the question is:
- **FeO is gangue and FeSiO3 is slag.**

### Final Answer:
FeO and FeSiO3 respectively are gangue and slag.

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