On passing electric current through acidified water :
(I) Hydrogen gas is collected over cathode and oxygen gas is collected over anode .
(II) Oxygen gas is collected over cathode and hydrogen gas is collection over anode.
(III) Ratio of Volume of hydrogen gas : oxygen gas = 1 : 2
(IV) Ratio of Volume of hydrogen gas : oxygen gas = 2 : 1
Select the correct statements :

Options

A. Both (I) and (III)
B. Both (I) and (IV)
C. Both (II) and (III)
D. Both (II) and (IV)

Explanation

To solve the question regarding the electrolysis of acidified water, we need to analyze the process and the results of passing electric current through it.

### Step-by-Step Solution:

1. **Understanding Electrolysis**:
- When electric current is passed through acidified water (water mixed with an acid like sulfuric acid), the water undergoes a process called electrolysis. This process involves the decomposition of water into its constituent gases: hydrogen and oxygen.

2. **Identifying the Electrodes**:
- In electrolysis, there are two electrodes: the cathode (negative electrode) and the anode (positive electrode).
- At the cathode, reduction occurs, leading to the formation of hydrogen gas (H₂).
- At the anode, oxidation occurs, leading to the formation of oxygen gas (O₂).

3. **Gas Collection**:
- Therefore, hydrogen gas is collected over the cathode, and oxygen gas is collected over the anode.
- This confirms statement (I): "Hydrogen gas is collected over cathode and oxygen gas is collected over anode."

4. **Volume Ratio of Gases**:
- According to the stoichiometry of the electrolysis of water, for every 2 volumes of hydrogen gas produced, 1 volume of oxygen gas is produced.
- This means the ratio of the volume of hydrogen gas to the volume of oxygen gas is 2:1.
- Thus, statement (III) is incorrect, and statement (IV) is correct: "Ratio of Volume of hydrogen gas : oxygen gas = 2 : 1."

5. **Evaluating Other Statements**:
- Statement (II) is incorrect because it states that oxygen gas is collected over the cathode and hydrogen gas over the anode, which is not true based on the electrolysis process.

### Summary of Correct Statements:
- The correct statements are:
- (I) Hydrogen gas is collected over cathode and oxygen gas is collected over anode.
- (IV) Ratio of Volume of hydrogen gas : oxygen gas = 2 : 1.