During reduction of `ZnO` to `Zn, C` is more efficient than `CO`.
The standard free energy of formation of `CO_(2)` from `CO` is always higher than that of `ZnO`.

Options

A. If both (A) and ( R) are correct and ( R) is the correct explanation of (A).
B. If both (A) and ( R) are correct, but ( R) is not the correct explanation of (A).
C. If (A) is correct, but ( R) is incorrect.
D. If (A) is incorrect, but ( R) is correct.

Explanation

To solve the question, we need to analyze the reduction of zinc oxide (ZnO) to zinc (Zn) using carbon (C) and carbon monoxide (CO). We will also consider the standard free energy of formation for CO2 and ZnO.

### Step-by-Step Solution:

1. **Understanding the Reduction Process**:
The reduction of zinc oxide (ZnO) to zinc (Zn) can be represented by the following reaction:
\[ \text{ZnO} + \text{C} \rightarrow \text{Zn} + \text{CO} \]
This indicates that carbon is used to reduce zinc oxide to zinc, producing carbon monoxide as a byproduct.

**Hint**: Recall the general reaction for reduction processes involving oxides and carbon.

2. **Comparing Reducing Agents**:
In the context of reduction, we need to compare the efficiency of carbon (C) and carbon monoxide (CO) as reducing agents. The statement claims that carbon is more efficient than carbon monoxide for reducing ZnO.

**Hint**: Consider the thermodynamic stability of the products formed from the reducing agents.

3. **Standard Free Energy of Formation**:
The standard free energy of formation (ΔG°) values are crucial in determining the feasibility of the reduction reactions. The values given are:
- ΔG° for CO2 from CO: -237.2 kJ/mol
- ΔG° for ZnO: -318.2 kJ/mol

**Hint**: Remember that a more negative ΔG° indicates a more favorable reaction.

4. **Analyzing the Free Energy Values**:
The ΔG° value for ZnO is more negative than that of CO2, which implies that the formation of ZnO is thermodynamically more favorable than the formation of CO2 from CO. This suggests that carbon (C) is a better reducing agent than carbon monoxide (CO) when reducing ZnO.

**Hint**: Compare the ΔG° values to determine the relative stability of the compounds involved.

5. **Conclusion**:
Both assertions in the question are correct:
- Assertion: ZnO is reduced to Zn by carbon (C).
- Reason: The standard free energy of formation of CO2 from CO is always higher than that of ZnO.

However, the reason provided does not correctly explain why carbon is more efficient than carbon monoxide in this context.

Therefore, the final answer is that both the assertion and reason are correct, but the reason is not the correct explanation for the assertion.

**Final Answer**: Both the assertion and reason are correct, but the reason is not the correct explanation of the assertion. (Option 2 is correct.)