Which is the strongest acid in the following ?

Options

A. `H_(2)SO_(4)`
B. `HClO_(3)`
C. `HClO_(4)`
D. `H_(2)SO_(3)`

Explanation

To determine which is the strongest acid among the given options (H₂SO₄, HClO₃, HClO₄, and H₂SO₃), we will analyze the oxidation states of the central atoms in each acid and relate them to acidic strength.

### Step-by-Step Solution:

1. **Identify the Acids and Their Central Atoms**:
- H₂SO₄ (sulfuric acid) - Central atom: Sulfur (S)
- HClO₃ (chloric acid) - Central atom: Chlorine (Cl)
- HClO₄ (perchloric acid) - Central atom: Chlorine (Cl)
- H₂SO₃ (sulfurous acid) - Central atom: Sulfur (S)

2. **Calculate the Oxidation State of Sulfur in H₂SO₄**:
- The formula for oxidation state calculation is:
\[ \text{Oxidation state} = \text{(Sum of oxidation states of all atoms)} = 0 \]
- For H₂SO₄:
- Let the oxidation state of sulfur be \( x \).
- Hydrogen contributes \( +2 \) (2 × +1).
- Oxygen contributes \( -8 \) (4 × -2).
- Therefore, the equation is:
\[ 2 + x - 8 = 0 \implies x = +6 \]

3. **Calculate the Oxidation State of Sulfur in H₂SO₃**:
- For H₂SO₃:
- Let the oxidation state of sulfur be \( x \).
- Hydrogen contributes \( +2 \) (2 × +1).
- Oxygen contributes \( -6 \) (3 × -2).
- Therefore, the equation is:
\[ 2 + x - 6 = 0 \implies x = +4 \]

4. **Calculate the Oxidation State of Chlorine in HClO₃**:
- For HClO₃:
- Let the oxidation state of chlorine be \( x \).
- Hydrogen contributes \( +1 \).
- Oxygen contributes \( -6 \) (3 × -2).
- Therefore, the equation is:
\[ 1 + x - 6 = 0 \implies x = +5 \]

5. **Calculate the Oxidation State of Chlorine in HClO₄**:
- For HClO₄:
- Let the oxidation state of chlorine be \( x \).
- Hydrogen contributes \( +1 \).
- Oxygen contributes \( -8 \) (4 × -2).
- Therefore, the equation is:
\[ 1 + x - 8 = 0 \implies x = +7 \]

6. **Compare the Oxidation States**:
- H₂SO₄: +6
- H₂SO₃: +4
- HClO₃: +5
- HClO₄: +7

7. **Determine the Strongest Acid**:
- The strength of an acid is directly related to the oxidation state of the central atom. The higher the oxidation state, the stronger the acid.
- Among the acids, HClO₄ has the highest oxidation state of +7, making it the strongest acid.

### Conclusion:
The strongest acid among the given options is **HClO₄**.

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