Select the most ionic and most covalent compounds respectively from the following.
`CrO_5, Mn_2O_7, PbO, P_4O_10,SnO_2`

Options

A. `CrO_(5), Mn_(2)O_(7)`
B. `PbO, Mn_(2)O_(7)`
C. `CrO_(5), Fe_(2)O_(3)`
D. `CrO_(5), SnO_(2)`

Answer

To determine the most ionic and most covalent compounds from the given list of compounds (CrO5, Mn2O7, PbO, P4O10, SnO2), we will analyze the oxidation states of the metal ions in each compound and apply the concepts of polarizability and ionic character.

### Step-by-Step Solution:

1. **Identify the Oxidation States:**
- **CrO5:** Let the oxidation state of Cr be \( x \).
\[ x + 5(-2) = 0 \implies x - 10 = 0 \implies x = +6 \]
- **Mn2O7:** Let the oxidation state of Mn be \( x \).
\[ 2x + 7(-2) = 0 \implies 2x - 14 = 0 \implies 2x = 14 \implies x = +7 \]
- **PbO:** Let the oxidation state of Pb be \( x \).
\[ x + (-2) = 0 \implies x = +2 \]
- **P4O10:** Let the oxidation state of P be \( x \).
\[ 4x + 10(-2) = 0 \implies 4x - 20 = 0 \implies 4x = 20 \implies x = +5 \]
- **SnO2:** Let the oxidation state of Sn be \( x \).
\[ x + 2(-2) = 0 \implies x - 4 = 0 \implies x = +4 \]

2. **List the Oxidation States:**
- Cr in CrO5: +6
- Mn in Mn2O7: +7
- Pb in PbO: +2
- P in P4O10: +5
- Sn in SnO2: +4

3. **Determine Ionic and Covalent Character:**
- **Ionic Character:** Generally, ionic character is higher when the cation has a lower charge and larger size. Among the cations, Pb (with +2) has the lowest charge.
- **Covalent Character:** Covalent character is higher when the cation has a higher charge and smaller size. Here, Mn (with +7) has the highest charge.

4. **Conclusion:**
- The most ionic compound is **PbO** (due to Pb being +2).
- The most covalent compound is **Mn2O7** (due to Mn being +7).

### Final Answer:
- Most Ionic Compound: **PbO**
- Most Covalent Compound: **Mn2O7**