When 1.0 mol of compound Q is burnt in excess oxygen, 2.0 mol of carbon dioxide and 2.0 mol of steam are produced. Which of the following is the structural formula of compound Q?

Options

A. `H-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H`
B. `H-underset(H)underset(|)overset(H)overset(|)C-overset(H)overset(|)C=O`
C. `H-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-O-H`
D. `H-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-O-H`

Explanation

To determine the structural formula of compound Q, we need to analyze the products formed when it is burned in excess oxygen. The combustion of organic compounds typically produces carbon dioxide (CO2) and water (H2O).

### Step-by-Step Solution:

1. **Identify the Products of Combustion**:
- When 1.0 mol of compound Q is burnt, it produces 2.0 mol of carbon dioxide (CO2) and 2.0 mol of water (H2O).

2. **Determine the Number of Carbon Atoms**:
- Each mole of CO2 contains one carbon atom. Therefore, 2.0 moles of CO2 indicates that there are 2 carbon atoms in compound Q.

3. **Determine the Number of Hydrogen Atoms**:
- Each mole of water (H2O) contains two hydrogen atoms. Thus, 2.0 moles of water indicates that there are 4 hydrogen atoms in compound Q (2 moles x 2 H = 4 H).

4. **Construct the Empirical Formula**:
- From the above analysis, we can deduce that compound Q has 2 carbon atoms and 4 hydrogen atoms. This gives us the empirical formula C2H4.

5. **Identify Possible Structural Formulas**:
- The empirical formula C2H4 corresponds to several structural formulas, including:
- Ethylene (C2H4)
- Acetaldehyde (CH3CHO)
- However, since the question specifies the combustion products, we need to find a compound that fits the combustion reaction.

6. **Evaluate the Options**:
- Check the provided structural formulas in the options to see which one has 2 carbon atoms and 4 hydrogen atoms.
- The correct structural formula must match C2H4.

7. **Conclusion**:
- After evaluating the options, the structural formula that fits the criteria (2 carbon atoms and 4 hydrogen atoms) is CH3CHO, which is an aldehyde.

### Final Answer:
The structural formula of compound Q is CH3CHO.