Electrolysis is an important technique for extraction of metals, and each ion of the solution needs a minimum voltage to get discharged and this value is expressed in terms of discharge potential. For some metal ions the discharge potentials follow the order given below :
`Li^(+) gt K^(+) gt Ca^(2+) gt Na^(+) gt Mg^(2+) gt Al^(3+) gt Zn^(2+) gt Fe^(2+) gt Ni^(2+) gt H_(3)O^(+) gt Cu^(2+) gt Hg_(2)^(2+) gt Ag^(+) gt Au^(3+)`
For some anions the discharge potentials are in the order :
`SO_(4)^(2-) gt NO_(3)^(-) gt OH^(-) gt Br^(-) gt I^(-)`
When conc. `H_(2)SO_(4)` is electrolysed with high current using Pt electrodes, the product obtained at anode is :

Options

A. `SO_(2)`
B. `SO_(3)`
C. `O_(2)`
D. `H_(2)S_(2)O_(8)`

Answer

To solve the problem of identifying the product obtained at the anode when concentrated sulfuric acid is electrolyzed with high current using platinum electrodes, we can follow these steps:

### Step 1: Understand the Electrolysis Process
Electrolysis involves the breakdown of a compound into its components using electricity. In this case, we are electrolyzing concentrated sulfuric acid (H₂SO₄), which dissociates into ions in solution.

### Step 2: Identify the Ions Present
When concentrated sulfuric acid is dissolved in water, it dissociates into:
- H⁺ (hydrogen ions)
- SO₄²⁻ (sulfate ions)

Additionally, water also dissociates into:
- H₂O ↔ H⁺ + OH⁻

Thus, the ions present in the solution are H⁺, SO₄²⁻, and OH⁻.

### Step 3: Determine the Anode Reaction
At the anode, negatively charged ions (anions) migrate towards it. The relevant anions in this case are OH⁻ and SO₄²⁻. The discharge potential indicates which ion will be discharged preferentially.

### Step 4: Compare Discharge Potentials
From the provided order of discharge potentials:
- OH⁻ has a lower discharge potential than SO₄²⁻.

This means that OH⁻ will be discharged at the anode before SO₄²⁻.

### Step 5: Write the Reaction at the Anode
The reaction at the anode for the discharge of OH⁻ is:
\[ 4OH⁻ \rightarrow 2H₂O + O₂ + 4e⁻ \]
This indicates that oxygen gas (O₂) is produced at the anode.

### Step 6: Conclusion
Since we are interested in the product obtained at the anode during the electrolysis of concentrated sulfuric acid, the product is oxygen gas (O₂).

### Final Answer
The product obtained at the anode is **O₂ (oxygen gas)**.

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