During the formation of the slag by the reaction of flux and impurities which of the following is an example of acidic and basic flux?
(i) `FeO+SiO_(2)rarrFeSiO_(3)`
(ii) `SiO_(2)+MgOrarrMgSiO_(3)`

Options

A. (i) `SiO_(2)-" Acidc flux (ii) MgO - Basic flux"`
B. (i) `SiO_(2)-" Basic flux (ii) MgO - Acidic flux"`
C. (i) `SiO_(2)-" Basic flux (ii) MgO - Basic flux"`
D. (i) `SiO_(2)-" Acidic flux (ii) MgO - Acidic flux"`

Answer

To solve the question regarding the formation of slag by the reaction of flux and impurities, we need to identify which of the given reactions involves an acidic flux and which involves a basic flux.

### Step-by-Step Solution:

1. **Understanding Fluxes**:
- A flux is a substance added to a furnace to promote melting and to help remove impurities. Fluxes can be classified as acidic or basic based on their chemical nature.
- Acidic fluxes typically react with basic impurities, while basic fluxes react with acidic impurities.

2. **Analyzing the First Reaction**:
- The first reaction is:
\[ \text{FeO} + \text{SiO}_2 \rightarrow \text{FeSiO}_3 \]
- In this reaction, **SiO₂ (silicon dioxide)** acts as the acidic flux. It reacts with the basic impurity **FeO (iron(II) oxide)** to form **FeSiO₃ (iron silicate)**, which is the slag.

3. **Analyzing the Second Reaction**:
- The second reaction is:
\[ \text{SiO}_2 + \text{MgO} \rightarrow \text{MgSiO}_3 \]
- Here, **SiO₂** is again present as the acidic component. **MgO (magnesium oxide)** acts as the basic flux. In this case, the basic flux reacts with the acidic flux to form **MgSiO₃ (magnesium silicate)**.

4. **Identifying Acidic and Basic Fluxes**:
- From the first reaction, we conclude that **SiO₂ is the acidic flux** and **FeO is the basic impurity**.
- From the second reaction, **MgO is the basic flux** and **SiO₂ is the acidic flux**.

5. **Conclusion**:
- The first reaction shows an example of an acidic flux (SiO₂) reacting with a basic impurity (FeO).
- The second reaction shows a basic flux (MgO) reacting with an acidic flux (SiO₂).
- Therefore, both reactions illustrate the concept, but the question asks for an example of acidic and basic flux, leading us to conclude that the first reaction is the more straightforward example of this classification.

### Final Answer:
The correct answer is **option (i)**: `FeO + SiO₂ → FeSiO₃`, where SiO₂ is the acidic flux.