Estimation of oxidising substance involving the liberation of `I_(2)` and subsequent volumetric estimation of `I_(2)` are refferred to as
`2Cu^(2+)+4I^(Theta)rarr Cu_(2)I_(2)+I_(2)`
`I_(2)+ S_(2)O_(3)^(2-)rarr S_(4)O_(6)^(2-)+2I^(Theta)`

Options

A. Iodimetry
B. Iodometry
C. Oxidising
D. Reducing

Answer

To solve the question regarding the estimation of oxidizing substances involving the liberation of iodine (I₂) and its subsequent volumetric estimation, we will follow these steps:

### Step 1: Understand the Process
The question describes a method for estimating oxidizing agents that involves the generation of iodine gas (I₂) through a redox reaction. In this case, the oxidizing agent reacts with iodide ions (I⁻) to produce iodine.

**Hint:** Identify the role of the oxidizing agent and the iodide ions in the reaction.

### Step 2: Identify the Reactions
The reactions given are:
1. \( 2Cu^{2+} + 4I^{-} \rightarrow Cu_{2}I_{2} + I_{2} \)
2. \( I_{2} + S_{2}O_{3}^{2-} \rightarrow S_{4}O_{6}^{2-} + 2I^{-} \)

The first reaction shows the liberation of iodine gas from the reaction of the oxidizing agent (copper ions) with iodide ions. The second reaction involves the titration of the liberated iodine with thiosulfate ions (S₂O₃²⁻), which is a reducing agent.

**Hint:** Recognize the significance of each reaction in the context of the estimation process.

### Step 3: Differentiate Between Iodometry and Iodimetry
- **Iodometry**: This is the indirect method where the amount of an oxidizing agent is determined by the amount of iodine produced when it reacts with iodide ions. The iodine is then titrated with a reducing agent like sodium thiosulfate.
- **Iodimetry**: This is the direct method where the reducing agents are quantified directly by titrating them with iodine.

**Hint:** Remember that iodometry is used for oxidizing agents, while iodimetry is used for reducing agents.

### Step 4: Conclusion
Based on the reactions and methods discussed, the estimation of oxidizing substances involving the liberation of I₂ and its subsequent volumetric estimation is referred to as **Iodometry**.

**Final Answer:** The correct answer is **Iodometry**.