Pick out the correct set of statements for Hl.
1. It reduces iodic acid to `I_(2)`
2. It reduces `H_(2)SO_(4)` to `SO_(2)`
3. It decolourises acidified `KMnO_(4)`
4. It liberates `I_(2)` with`CuSO_(4)` solution

Options

A. 1, 2, 3
B. 1, 2, 4
C. 1, 3, 4
D. 1, 2, 3, 4

Answer

To solve the question regarding the correct set of statements for HI (Hydriodic acid), we will analyze each statement one by one.

### Step 1: Analyze Statement 1
**Statement:** HI reduces iodic acid to I2.

**Explanation:** Iodic acid (HIO3) can be reduced by HI to form iodine (I2) and water. The balanced reaction can be represented as:
\[ 5 \text{HI} + \text{HIO}_3 \rightarrow 3 \text{I}_2 + 3 \text{H}_2\text{O} \]
This statement is **correct**.

### Step 2: Analyze Statement 2
**Statement:** HI reduces H2SO4 to SO2.

**Explanation:** When HI is added to sulfuric acid (H2SO4), it can reduce H2SO4 to sulfur dioxide (SO2), along with the formation of iodine (I2) and water. The balanced reaction can be represented as:
\[ 8 \text{HI} + \text{H}_2\text{SO}_4 \rightarrow \text{SO}_2 + 4 \text{I}_2 + 4 \text{H}_2\text{O} \]
This statement is **correct**.

### Step 3: Analyze Statement 3
**Statement:** HI decolorizes acidified KMnO4.

**Explanation:** Acidified potassium permanganate (KMnO4) is purple in color. When HI is added, it reduces Mn from +7 to +2, resulting in the decolorization of the solution. The balanced reaction can be represented as:
\[ 3 \text{HI} + 2 \text{KMnO}_4 + 6 \text{H}_2\text{SO}_4 \rightarrow 5 \text{I}_2 + 2 \text{MnSO}_4 + K_2SO_4 + 8 \text{H}_2\text{O} \]
This statement is **correct**.

### Step 4: Analyze Statement 4
**Statement:** HI liberates I2 with CuSO4 solution.

**Explanation:** When HI reacts with copper(II) sulfate (CuSO4), it forms copper(I) iodide (CuI) and sulfuric acid (H2SO4). The reaction can be represented as:
\[ 2 \text{CuSO}_4 + 4 \text{HI} \rightarrow 2 \text{CuI} + 2 \text{H}_2\text{SO}_4 + \text{I}_2 \]
This shows that I2 is liberated in the process. This statement is **correct**.

### Conclusion
All four statements regarding HI are correct. Therefore, the correct answer is that all statements (1, 2, 3, and 4) are true.

### Final Answer:
The correct set of statements for HI is: **1, 2, 3, and 4**.

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