12 g of impure cyanogen undergoes hydrolysis by two different paths.
(i). `(CN)_(2)+4H_(2)Oto(NH_(4))_(2)C_(2)O_(4)`
(ii). `(CN)_(2)+2H_(2)OtoNH_(2)CONH_(2)`
When 11.52 g of pure ammonium carbonate `[(NH_(4))_(2)CO_(3)]` was heated, the exact amount of urea was obtained. 20 " mL of " 1.6 M acidic `KMnO_(4)` is required to completely oxidise `(NH_(4))_(2)C_(2)O_(4)`.
Q. In which reaction, carbon is oxidised?

Options

A. Reaction (i)
B. Reaction (ii)
C. Both
D. none

Explanation

To determine in which reaction carbon is oxidized, we need to analyze the oxidation states of carbon in both reactions.

### Step-by-Step Solution:

1. **Identify the Reactions**:
- Reaction (i): \( \text{(CN)}_2 + 4 \text{H}_2\text{O} \rightarrow \text{(NH}_4)_2\text{C}_2\text{O}_4 \)
- Reaction (ii): \( \text{(CN)}_2 + 2 \text{H}_2\text{O} \rightarrow \text{NH}_2\text{CONH}_2 \)

2. **Determine Oxidation States in Reaction (i)**:
- In \( \text{(NH}_4)_2\text{C}_2\text{O}_4 \), the oxalate ion \( \text{C}_2\text{O}_4^{2-} \) has carbon in the +3 oxidation state.
- For each carbon in \( \text{C}_2\text{O}_4^{2-} \), the oxidation state can be calculated as follows:
- Let the oxidation state of carbon be \( x \).
- The equation for the charge balance is: \( 2x + 4(-2) = -2 \) (total charge of oxalate).
- This simplifies to \( 2x - 8 = -2 \) leading to \( 2x = 6 \) or \( x = +3 \).
- Therefore, the oxidation state of carbon in this reaction remains +3.

3. **Determine Oxidation States in Reaction (ii)**:
- In urea \( \text{NH}_2\text{CONH}_2 \), the carbon is bonded to two nitrogen atoms and one oxygen atom.
- The oxidation state of carbon can be calculated similarly:
- Let the oxidation state of carbon be \( y \).
- The equation for the charge balance is: \( y + 2(-3) + (-2) = 0 \) (total charge of urea).
- This simplifies to \( y - 6 = 0 \) leading to \( y = +4 \).
- Therefore, the oxidation state of carbon in this reaction changes from +3 (in cyanogen) to +4 (in urea).

4. **Conclusion**:
- In Reaction (i), the carbon oxidation state remains +3.
- In Reaction (ii), the carbon oxidation state increases from +3 to +4.
- Since oxidation is defined as an increase in oxidation state, carbon is oxidized in Reaction (ii).

### Final Answer:
Carbon is oxidized in Reaction (ii): \( \text{(CN)}_2 + 2 \text{H}_2\text{O} \rightarrow \text{NH}_2\text{CONH}_2 \).

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