`H_(2)C_(2)O_(4)overset(triangle)to"gas"(A)+"gas"(B)+"liquid"(C)`. Gas(A) burns with a blue flame and is oxidised to gas(B).
`"Gas"(A)+Cl_(2)toDtooverset(NH_(3),triangle)toE`
A,B,C,D and E are

Options

A. `CO_(2),Co,H_(2)O,HCONH_(2)`
B. `CO,CO_(2),CoCl_(2),HCONH_(2)`
C. `CO,CO_(2),H_(2)O,COCl_(2),NH_(2)CONH_(2)`
D. `CO,CO_(2),H_(20O,COCl_(2)`

Answer

To solve the question step by step, we will analyze the decomposition of oxalic acid (H₂C₂O₄) and identify the gases and liquids produced during the reaction, as well as the subsequent reactions involving these products.

### Step 1: Identify the decomposition products of oxalic acid (H₂C₂O₄)
When oxalic acid is heated, it decomposes to form:
- **Gas A**
- **Gas B**
- **Liquid C**

The decomposition reaction can be represented as:
\[ \text{H}_2\text{C}_2\text{O}_4 \xrightarrow{\Delta} \text{Gas A} + \text{Gas B} + \text{Liquid C} \]

### Step 2: Determine the nature of Gas A
It is given that Gas A burns with a blue flame and is oxidized to Gas B. A gas that burns with a blue flame is typically carbon monoxide (CO), which is known for its blue flame during combustion.

### Step 3: Identify Gas B
Gas B is the product of the oxidation of Gas A (CO). When carbon monoxide is oxidized, it forms carbon dioxide (CO₂). Therefore, we can conclude:
- **Gas A = Carbon monoxide (CO)**
- **Gas B = Carbon dioxide (CO₂)**

### Step 4: Identify Liquid C
During the decomposition of oxalic acid, water (H₂O) is also produced as a liquid. Therefore:
- **Liquid C = Water (H₂O)**

### Step 5: Reaction of Gas A with Chlorine (Cl₂)
Gas A (CO) reacts with chlorine gas (Cl₂) to form a compound D. The reaction is:
\[ \text{CO} + \text{Cl}_2 \rightarrow \text{D} \]
The product of this reaction is phosgene (COCl₂).

### Step 6: Reaction of Compound D with Ammonia (NH₃)
Compound D (phosgene) reacts with ammonia when heated to form compound E. The reaction can be represented as:
\[ \text{COCl}_2 + 2\text{NH}_3 \rightarrow \text{E} \]
The product of this reaction is urea (NH₂CONH₂).

### Summary of the Identified Compounds
- **Gas A = Carbon monoxide (CO)**
- **Gas B = Carbon dioxide (CO₂)**
- **Liquid C = Water (H₂O)**
- **Compound D = Phosgene (COCl₂)**
- **Compound E = Urea (NH₂CONH₂)**

### Final Answer
Thus, the final identification of A, B, C, D, and E is:
- A = Carbon monoxide (CO)
- B = Carbon dioxide (CO₂)
- C = Water (H₂O)
- D = Phosgene (COCl₂)
- E = Urea (NH₂CONH₂)