Which of the following does not exist?

Options

A. `HS_(6)`
B. `HPO_(4)`
C. `FeI_(3)`
D. `HClO_(4)`

Explanation

To determine which of the given molecules does not exist, we will analyze each option based on their oxidation states and the feasibility of their structures.

### Step 1: Analyze Hs6
- **Oxidation State Calculation**: Let the oxidation state of sulfur (S) be \( x \). The oxidation state of hydrogen (H) is +1.
- The formula for the overall charge is:
\[ 6(+1) + x = 0 \]
This simplifies to:
\[ x + 6 = 0 \implies x = -6 \]
- **Feasibility**: A sulfur atom cannot have a -6 oxidation state. Additionally, hydrogen can only form a maximum of 2 bonds (accommodating 2 electrons). To bond with 6 sulfur atoms, it would need to accommodate 12 electrons, which is not possible.

### Conclusion for Hs6:
- **Result**: Hs6 does not exist.

### Step 2: Analyze HpO4
- **Oxidation State Calculation**: Let the oxidation state of phosphorus (P) be \( x \). The oxidation states are:
- H: +1
- O: -2 (4 oxygen atoms)
- The formula for overall charge is:
\[ +1 + x + 4(-2) = 0 \]
This simplifies to:
\[ x - 8 + 1 = 0 \implies x = 7 \]
- **Feasibility**: Phosphorus can have a maximum oxidation state of +5 (due to its valence electrons). Therefore, +7 is not possible.

### Conclusion for HpO4:
- **Result**: HpO4 does not exist.

### Step 3: Analyze FeI3
- **Oxidation State Calculation**: Iron (Fe) can exist in +2 or +3 oxidation states. For FeI3, if we assume Fe is in +3 state:
- Iodine (I) is -1.
- The formula for overall charge is:
\[ x + 3(-1) = 0 \implies x - 3 = 0 \implies x = +3 \]
- **Feasibility**: FeI3 is a large anion and cannot stabilize Fe in +3 state due to size and charge considerations. Therefore, Fe+ does not exist in this compound.

### Conclusion for FeI3:
- **Result**: FeI3 does not exist.

### Step 4: Analyze HClO4
- **Oxidation State Calculation**: Let the oxidation state of chlorine (Cl) be \( x \). The oxidation states are:
- H: +1
- O: -2 (4 oxygen atoms)
- The formula for overall charge is:
\[ +1 + x + 4(-2) = 0 \]
This simplifies to:
\[ x - 8 + 1 = 0 \implies x = +7 \]
- **Feasibility**: Chlorine can have an oxidation state of +7, which is possible since it has 7 valence electrons.

### Conclusion for HClO4:
- **Result**: HClO4 does exist.

### Final Answer:
The compounds that do not exist are **Hs6, HpO4, and FeI3**.