An organic compound 'A' on heating with concentrated `H_(2)SO_(4)` forms a compound 'B' which on addition of one mole of hydrogen in presence of Ni forms a compound 'C'. One mole of compound 'C' on combustion forms two moles of `CO_(2)` and three moles of `H_(2)O`.
Which of the following represents the compound 'C' ?

Options

A. `C_(2)H_(6)`, a saturated hydrocarbon
B. `C_(2)H_(4)`, an unsaturated hydrocarbon
C. HCOOH, an unsaturated acid
D. `C_(2)H_(5)OH`, a saturated alcohol

Explanation

To solve the problem step by step, we need to analyze the information given about the organic compounds A, B, and C.

### Step 1: Identify Compound A
The problem states that an organic compound 'A' is heated with concentrated sulfuric acid (H₂SO₄). This reaction typically involves dehydration of an alcohol, leading to the formation of an alkene.

**Hint:** Think about common alcohols that can undergo dehydration.

### Step 2: Determine the Structure of Compound B
Since we are starting with an alcohol, let's assume compound A is ethanol (C₂H₅OH). When ethanol is heated with concentrated H₂SO₄, it undergoes dehydration to form ethene (C₂H₄). Therefore, compound B is ethene.

**Hint:** Remember that dehydration reactions remove water and often lead to the formation of double bonds.

### Step 3: Identify Compound C
The next step involves the addition of one mole of hydrogen (H₂) to compound B (ethene) in the presence of nickel (Ni). This is a hydrogenation reaction, which converts the alkene (ethene) into an alkane. The product of this reaction is ethane (C₂H₆), which is compound C.

**Hint:** Hydrogenation reactions typically convert unsaturated hydrocarbons (like alkenes) into saturated hydrocarbons (like alkanes).

### Step 4: Combustion of Compound C
The problem states that one mole of compound C (ethane) on combustion produces two moles of CO₂ and three moles of H₂O. The combustion reaction for ethane can be represented as follows:

\[ \text{C}_2\text{H}_6 + 7/2 \text{O}_2 \rightarrow 2 \text{CO}_2 + 3 \text{H}_2\text{O} \]

This confirms that the combustion of ethane produces the correct stoichiometric amounts of carbon dioxide and water.

**Hint:** Check the balanced combustion equation to verify the products formed.

### Conclusion
Based on the above steps, we conclude that compound C is ethane (C₂H₆).

### Final Answer
The compound 'C' is **C₂H₆ (ethane)**.