Sodium salt of an organic acid 'X' produces effervescence with conc. `H_(2)SO_(4)`. 'X' reacts with the acidified aqueous `CaCl_(2)` solution to give a white precipitate which decolourises acidic solution of `KMnO_(4) 'X'` is

Options

A. `6.00 kJ "mol"^(-1)`
B. `5.81 kJ "mol"^(-1)`
C. `5.44 kJ "mol"^(-1)`
D. `6.56 kJ "mol"^(-1)`

Answer

To solve the problem, we need to identify the organic acid 'X' based on the clues provided in the question. Let's break it down step by step.

### Step 1: Analyze the first clue
The first clue states that the sodium salt of the organic acid 'X' produces effervescence with concentrated sulfuric acid (H₂SO₄).

- **Interpretation**: Effervescence typically indicates the release of a gas, which in this case is likely carbon dioxide (CO₂). This suggests that 'X' could be an acid that, when in its sodium salt form, reacts with H₂SO₄ to release CO₂.

### Step 2: Identify the possible organic acid
The most common organic acids that produce CO₂ upon reaction with strong acids are carboxylic acids, particularly those that form carbonates or bicarbonates.

- **Hypothesis**: One likely candidate is oxalic acid (H₂C₂O₄), which forms sodium oxalate (Na₂C₂O₄) as its sodium salt. When sodium oxalate reacts with concentrated H₂SO₄, it can produce CO₂ gas.

### Step 3: Analyze the second clue
The second clue states that 'X' reacts with acidified aqueous CaCl₂ solution to give a white precipitate.

- **Interpretation**: The white precipitate formed in this reaction is likely calcium oxalate (CaC₂O₄), which is known to be a white solid. This supports our hypothesis that 'X' is oxalic acid.

### Step 4: Analyze the third clue
The third clue mentions that 'X' decolorizes an acidic solution of potassium permanganate (KMnO₄).

- **Interpretation**: Decolorization of KMnO₄ in acidic medium indicates a reducing agent is present. Oxalic acid is known to reduce KMnO₄, thus confirming that 'X' is indeed oxalic acid.

### Conclusion
Based on the analysis of all three clues, we conclude that the organic acid 'X' is sodium oxalate (the sodium salt of oxalic acid).

### Final Answer
**X is sodium oxalate (Na₂C₂O₄)**.

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