`CaC_2+H_2O to A overset(H_2SO_4//HgSO_4)toB`. Identify A and B in the given reaction

Options

A. `C_2H_2` and `CH_3CHO`
B. `CH_4` and HCOOH
C. `C_2H_4` and `CH_3COOH`
D. `C_2H_2` and `CH_3COOH`

Explanation

To solve the given reaction step by step, let's break it down:

### Step 1: Identify the Reactants
The reaction starts with calcium carbide (CaC₂) and water (H₂O).

### Step 2: Reaction of Calcium Carbide with Water
When calcium carbide reacts with water, it produces calcium hydroxide (Ca(OH)₂) and ethyne (C₂H₂). The balanced equation for this reaction is:
\[ \text{CaC}_2 + 2 \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{C}_2\text{H}_2 \]

Here, **A** is identified as ethyne (C₂H₂).

### Step 3: Reaction of Ethyne with Sulfuric Acid and Mercury(II) Sulfate
Next, ethyne (C₂H₂) is treated with sulfuric acid (H₂SO₄) in the presence of mercury(II) sulfate (HgSO₄). This reaction leads to the formation of acetaldehyde (CH₃CHO). The reaction can be represented as:
\[ \text{C}_2\text{H}_2 + \text{H}_2\text{SO}_4 \xrightarrow{\text{HgSO}_4} \text{CH}_3\text{CHO} \]

Here, **B** is identified as acetaldehyde (CH₃CHO).

### Conclusion
Thus, the final identification is:
- **A** = Ethyne (C₂H₂)
- **B** = Acetaldehyde (CH₃CHO)

### Final Answer
A: C₂H₂ (Ethyne)
B: CH₃CHO (Acetaldehyde)

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