Which of the following statement is correct about CO ?

Options

A. It reduces aqueous solution of `PdCl_2` to metallic Pd
B. CO is neutral oxide and acts as a fuel
C. In laboratory it is prepared by dehydrating HCOOH with conc. `H_2SO_4`
D. All are correct

Answer

To determine which statement about carbon monoxide (CO) is correct, we will analyze each of the provided options step by step.

### Step 1: Analyze Option 1
**Statement:** "It reduces aqueous solution of PdCl2 to metallic Pd."

- **Explanation:** Carbon monoxide is known to act as a reducing agent. In the presence of water, it can reduce palladium(II) chloride (PdCl2) to metallic palladium (Pd). The reaction can be represented as:

\[ \text{PdCl}_2 + \text{CO} + \text{H}_2\text{O} \rightarrow \text{Pd} + \text{HCl} + \text{CO}_2 \]

- **Conclusion:** This statement is correct.

### Step 2: Analyze Option 2
**Statement:** "Carbon monoxide is a neutral oxide and acts as fuel."

- **Explanation:** Carbon monoxide is classified as a neutral oxide because it does not exhibit acidic or basic properties. It does not react with acids or bases to form salts. Additionally, CO is used as a fuel in various industrial processes, including the production of energy and chemicals.

- **Conclusion:** This statement is also correct.

### Step 3: Analyze Option 3
**Statement:** "In laboratory, it is prepared by dehydrating formic acid with concentrated H2SO4."

- **Explanation:** Formic acid (HCOOH) can be dehydrated using concentrated sulfuric acid (H2SO4), which is a strong dehydrating agent. The reaction produces carbon monoxide and water:

\[ \text{HCOOH} \xrightarrow{\text{H}_2\text{SO}_4} \text{CO} + \text{H}_2\text{O} \]

- **Conclusion:** This statement is correct.

### Step 4: Analyze Option 4
**Statement:** "All the above options are correct."

- **Explanation:** Since we have established that options 1, 2, and 3 are all correct, it follows that option 4, which states that all the above options are correct, is also correct.

### Final Conclusion
The correct answer is option 4: "All the above options are correct."

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