The incorrect statement among the following is

Options

A. Hydrogen is used to reduce `NiO`
B. Zirconium is refined by Van Arkel method
C. The sulphide ore galena is concentrated by froth flotation
D. In the metallurgy of iron, flux used is `SiO_(2)`

Explanation

To identify the incorrect statement among the options provided, we will analyze each statement one by one.

### Step 1: Analyze Statement A
**Statement A:** "Hydrogen is used to reduce nickel oxide."
- This statement is **correct**. Nickel oxide (NiO) can be reduced to nickel (Ni) using hydrogen (H₂) as a reducing agent. The reaction is:
\[ \text{NiO} + \text{H}_2 \rightarrow \text{Ni} + \text{H}_2\text{O} \]

### Step 2: Analyze Statement B
**Statement B:** "Zirconium is refined by Wen-Arkell method."
- This statement is **correct**. The Wen-Arkell method is indeed used for the refining of zirconium and titanium, where the metal is heated in an evacuated vessel with iodine to remove impurities such as oxygen and nitrogen.

### Step 3: Analyze Statement C
**Statement C:** "The sulphide ore galena is concentrated by froth flotation."
- This statement is **correct**. Galena (PbS) is a sulphide ore and is concentrated using the froth flotation method, which is effective for sulphide ores due to their preferential wetting properties.

### Step 4: Analyze Statement D
**Statement D:** "In metallurgy of iron, the flux used is SiO2."
- This statement is **incorrect**. In the metallurgy of iron, the flux used is typically calcium oxide (CaO), not silicon dioxide (SiO₂). The SiO₂ present is actually the gangue, which reacts with the flux (CaO) to form slag (CaSiO₃).

### Conclusion
The incorrect statement among the options is **Statement D**.

### Final Answer
**The incorrect statement is D: "In metallurgy of iron, the flux used is SiO2."**

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