Which one of the following statements is not correct?

Options

A. Mercury (II) iodide dissolves in excess of potassium iodide solution
B. Tin (IV) chloride is made by dissolving tin solution in concentrated hydrochloric acid
C. Zinc dissolves in sodium hydroxide solution
D. Carbon monoxide reduces iron (III) oxide to iron

Explanation

To determine which statement is not correct, we will analyze each option provided in the question step by step.

### Step 1: Analyze the first statement
**Statement:** Mercury(II) iodide dissolves in excess potassium iodide solution.

**Explanation:** This statement is correct. When mercury(II) iodide (HgI2) is added to excess potassium iodide (KI), a complex ion is formed, specifically K2HgI4. The reaction can be represented as:
\[ \text{HgI}_2 + 2 \text{KI} \rightarrow \text{K}_2\text{HgI}_4 \]

### Step 2: Analyze the second statement
**Statement:** Zinc dissolves in sodium hydroxide solution.

**Explanation:** This statement is also correct. Zinc reacts with sodium hydroxide (NaOH) to form sodium zincate (Na2ZnO2) and hydrogen gas (H2). The reaction can be represented as:
\[ \text{Zn} + 2 \text{NaOH} \rightarrow \text{Na}_2\text{ZnO}_2 + \text{H}_2 \]

### Step 3: Analyze the third statement
**Statement:** Carbon monoxide reduces iron(III) oxide to iron.

**Explanation:** This statement is correct as well. Carbon monoxide (CO) can reduce iron(III) oxide (Fe2O3) to iron (Fe). The reaction can be represented as:
\[ \text{Fe}_2\text{O}_3 + 3 \text{CO} \rightarrow 2 \text{Fe} + 3 \text{CO}_2 \]

### Step 4: Analyze the fourth statement
**Statement:** Tin(IV) chloride is made by dissolving tin in concentrated hydrochloric acid.

**Explanation:** This statement is not correct. Tin(IV) chloride (SnCl4) is actually produced by the reaction of tin with chlorine gas, not by dissolving tin in hydrochloric acid. The correct reaction is:
\[ \text{Sn} + 2 \text{Cl}_2 \rightarrow \text{SnCl}_4 \]

### Conclusion
After analyzing all the statements, the statement that is not correct is:
**Tin(IV) chloride is made by dissolving tin in concentrated hydrochloric acid.**

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