The set of compounds which does not exist, is

Options

A. `PbI_(4),BiCl_(5),PH_(5)`
B. `XeF_(2),XeF_(3)^(-),XeF_(4)`
C. `FeI_(3),CuI_(2),CuCl_(2)`
D. `Hg(OH)_(2),Ag_(2)O,V_(2)SO_(4)`

Explanation

To determine the set of compounds that do not exist, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Analyze Option A: PbI4, BiCl5, Ph5**
- **PbI4**: Lead (Pb) typically exhibits a +2 oxidation state due to the inert-pair effect. When attempting to form PbI4, it decomposes into PbI2 and I2, indicating that Pb cannot stabilize a +4 oxidation state. Thus, PbI4 does not exist.
- **BiCl5**: Bismuth (Bi) also shows a tendency to stabilize in a +3 oxidation state due to the inert-pair effect. When BiCl5 is formed, it decomposes into BiCl3 and Cl2, indicating that Bi cannot stabilize a +5 oxidation state. Hence, BiCl5 does not exist.
- **Ph5**: Phosphorus (Ph) does not have the ability to expand its valence shell to accommodate five bonds due to the absence of d-orbitals in the second period. Therefore, Ph5 does not exist.

2. **Analyze Option B: XeF2, XeF3-, XeF4**
- All these compounds are known to exist. Xenon can form stable compounds with fluorine in these oxidation states.

3. **Analyze Option C: FeI3, CuI2, CuCl2**
- All these compounds are known to exist. Iron and copper can stabilize in these oxidation states.

4. **Analyze Option D: Mercury Hydroxide, Ag2O, V2SO4**
- All these compounds are known to exist. Mercury, silver, and vanadium can stabilize in these oxidation states.

### Conclusion:
Based on the analysis, the set of compounds that do not exist is **Option A: PbI4, BiCl5, Ph5**.