The vapour of an organic compound requires three times its own volume of oxygen for complete combustion and produces twice its own volume of carbon dioxide . Which of the following compounds would give these results ?

Options

A. `CH_(3)CHO`
B. `C_(2)H_(5)OH`
C. `CH_(3)COOH`
D. `C_(2)H_(4)`

Answer

To solve the problem, we need to analyze the combustion reactions of the given organic compounds and determine which ones require three times their volume of oxygen and produce twice their volume of carbon dioxide.

### Step-by-Step Solution:

1. **Understanding the Problem**:
- We need to find an organic compound (let's denote its volume as \( V \)) that requires \( 3V \) of oxygen (\( O_2 \)) for complete combustion and produces \( 2V \) of carbon dioxide (\( CO_2 \)).
- According to the volume ratio for gases, we can express this as:
\[ \text{Organic Compound} : O_2 : CO_2 = 1 : 3 : 2 \]

2. **Identifying the Compounds**:
- Let's consider the four organic compounds provided in the options. We will write their combustion reactions and analyze the stoichiometry.

3. **Combustion of Ethanol (\( C_2H_5OH \))**:
- The balanced equation for the combustion of ethanol is:
\[ C_2H_5OH + 3O_2 \rightarrow 2CO_2 + 3H_2O \]
- Here, 1 volume of ethanol requires 3 volumes of oxygen and produces 2 volumes of carbon dioxide. This matches our requirement.

4. **Combustion of Acetic Acid (\( CH_3COOH \))**:
- The balanced equation for acetic acid is:
\[ CH_3COOH + 2O_2 \rightarrow 2CO_2 + 2H_2O \]
- Here, 1 volume of acetic acid requires 2 volumes of oxygen and produces 2 volumes of carbon dioxide. This does not match our requirement.

5. **Combustion of Ethyne (\( C_2H_2 \))**:
- The balanced equation for ethyne is:
\[ C_2H_2 + 2.5O_2 \rightarrow 2CO_2 + H_2O \]
- This can also be expressed as:
\[ C_2H_2 + 3O_2 \rightarrow 2CO_2 + 2H_2O \]
- Here, 1 volume of ethyne requires 3 volumes of oxygen and produces 2 volumes of carbon dioxide. This matches our requirement.

6. **Conclusion**:
- Based on the analysis, the compounds that satisfy the conditions of requiring three times their volume of oxygen and producing twice their volume of carbon dioxide are:
- Ethanol (\( C_2H_5OH \))
- Ethyne (\( C_2H_2 \))

### Final Answer:
The compounds that would give the required results are **Ethanol (A)** and **Ethyne (D)**.