Which of the following shows highest oxidation number of combined state:

Options

A. Os
B. Ru
C. Both (1) and (2)
D. None

Answer

To determine which of the given elements shows the highest oxidation number in a combined state, we will analyze the oxidation states of the elements mentioned, specifically osmium (Os) and ruthenium (Ru).

### Step-by-Step Solution:

1. **Identify the Elements**: The elements in question are osmium (Os) and ruthenium (Ru). Both of these elements belong to the d-block of the periodic table.

2. **Understand Oxidation States**: Oxidation states indicate the degree of oxidation of an atom in a compound. Elements can exhibit various oxidation states depending on their chemical environment.

3. **Determine Oxidation States of Osmium (Os)**:
- Osmium can exhibit a wide range of oxidation states:
- Negative: -4, -2, -1
- Zero: 0
- Positive: +1, +2, +3, +4, +5, +6, +7, +8
- The highest oxidation state of osmium is **+8**.

4. **Determine Oxidation States of Ruthenium (Ru)**:
- Ruthenium also exhibits a variety of oxidation states:
- Negative: -4, -2
- Zero: 0
- Positive: +1, +2, +3, +4, +5, +6, +7, +8
- The highest oxidation state of ruthenium is also **+8**.

5. **Compare the Highest Oxidation States**:
- Both osmium and ruthenium can achieve the highest oxidation state of **+8**.

6. **Conclusion**: Since both elements can show the highest oxidation state of +8, the answer to the question is that both osmium and ruthenium exhibit the highest oxidation number in a combined state.

### Final Answer:
The answer is **Option C**: Both osmium (Os) and ruthenium (Ru) show the highest oxidation number of +8 in a combined state.