An organic compound (A) reacts with `H_(2)` to give (B) and (C) successively. On ozonolysis of (A), tow aldehyes (D) `C_(2)H_(4)O` and (E) `C_(2)H_(2)O_(2)` and formed. On ozonolysis of (B) only propanal is formed. What are (A) to (E) ?

Answer

To solve the problem step-by-step, let's analyze the information provided and deduce the structures of compounds A to E.

### Step 1: Identify Compound A
The question states that compound A reacts with hydrogen (H₂) to yield compounds B and C successively. The ozonolysis of A produces two aldehydes, D (C₂H₄O) and E (C₂H₂O₂).

Given that D is C₂H₄O, which corresponds to acetaldehyde (CH₃CHO), and E is C₂H₂O₂, which corresponds to glycolaldehyde (HOCH₂CHO), we can deduce that compound A must be an alkene that can yield these products upon ozonolysis.

### Step 2: Determine the Structure of Compound A
The ozonolysis of compound A produces two aldehydes. A likely candidate for A is 2-hexene (CH₃CH=CHCH₂CH₂CH₃). When ozonolysis occurs, the double bond breaks and forms two aldehydes:
- One part yields acetaldehyde (D, C₂H₄O).
- The other part yields glycolaldehyde (E, C₂H₂O₂).

### Step 3: Identify Compound B
Compound B is formed by the hydrogenation of compound A. The hydrogenation of 2-hexene (A) will convert the double bond into a single bond, resulting in hexane (C₆H₁₄).

### Step 4: Identify Compound C
Compound C is formed by further hydrogenation of compound B. Since B is hexane, further hydrogenation does not change the structure, as hexane is already fully saturated. Therefore, compound C is also hexane (C₆H₁₄).

### Step 5: Identify Compound D
As deduced earlier, compound D is acetaldehyde (C₂H₄O), which has the structure CH₃CHO.

### Step 6: Identify Compound E
Compound E is glycolaldehyde (C₂H₂O₂), which has the structure HOCH₂CHO.

### Step 7: Confirm the Ozonolysis of Compound B
The question states that ozonolysis of compound B yields only propanal. Since B is hexane, ozonolysis will not yield propanal. However, if we consider that B could be a different alkene, such as 1-hexene, ozonolysis would yield propanal (C₃H₆O) and another aldehyde.

### Final Summary of Compounds
- **A**: 2-Hexene (CH₃CH=CHCH₂CH₂CH₃)
- **B**: Hexane (C₆H₁₄)
- **C**: Hexane (C₆H₁₄)
- **D**: Acetaldehyde (C₂H₄O, CH₃CHO)
- **E**: Glycolaldehyde (C₂H₂O₂, HOCH₂CHO)

### Summary of Compounds A to E
- **A**: 2-Hexene
- **B**: Hexane
- **C**: Hexane
- **D**: Acetaldehyde
- **E**: Glycolaldehyde