Point out A in the given reaction sequence
`Aoverset(O_(3)//H_(2)O_(2))rarrBoverset(Delta)rarr2CH_(3)COOH+CO_(2)`

Options

A.
B.
C.
D.

Answer

To determine compound A in the given reaction sequence, we will analyze the reactions step by step.

### Step 1: Understanding the Reaction Sequence
The reaction sequence given is:
\[ A \overset{O_3/H_2O_2}{\rightarrow} B \overset{\Delta}{\rightarrow} 2 \text{CH}_3\text{COOH} + \text{CO}_2 \]

Here, A reacts with ozone (O3) and hydrogen peroxide (H2O2) to form B, and upon heating (Δ), B decomposes to yield two molecules of acetic acid (CH3COOH) and carbon dioxide (CO2).

### Step 2: Identifying the Type of Reaction
The reaction involving ozone and hydrogen peroxide suggests that we are dealing with oxidative ozonolysis, which typically occurs with alkenes. This process involves the cleavage of double bonds in alkenes to form carbonyl compounds.

### Step 3: Analyzing Possible Structures for A
We need to identify an alkene (compound A) that, when subjected to oxidative ozonolysis, will yield compound B.

1. **Cyclopentene**: If we consider cyclopentene, ozonolysis would yield a product that, upon heating, would not produce two acetic acid molecules. Instead, it would yield butanoic acid and carbon dioxide.

2. **Cyclohexene**: Similarly, cyclohexene would yield pentanoic acid upon heating, which also does not match our requirement of producing two acetic acid molecules.

3. **Cyclohexadiene**: This compound has two double bonds. Upon ozonolysis, both double bonds would cleave, producing two molecules of acetic acid (CH3COOH) after the removal of carbon dioxide. This matches our requirement perfectly.

4. **Cyclobutadiene**: This compound would yield oxalic acid, which does not lead to the formation of acetic acid upon heating.

### Conclusion
After analyzing the possible structures for A, we conclude that the correct answer is:
\[ \text{A = Cyclohexadiene} \]