Which of the following can act as an oxidising agent ?

Options

A. `H_(2)SO_(4)`
B. `HNO_(3)`
C. `KMnO_(4)`
D. `K_(2)Cr_(2)O_(7)`

Answer

To determine which of the given compounds can act as an oxidizing agent, we need to analyze the oxidation states of the central atoms in each compound. An oxidizing agent is a substance that can accept electrons and, in the process, gets reduced itself.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are H2SO4, HNO3, KMnO4, and K2Cr2O7.

2. **Determine the Oxidation State of Sulfur in H2SO4**:
- Let the oxidation state of sulfur be \( x \).
- The equation for H2SO4 is:
\[ x + 2(+1) + 4(-2) = 0 \]
- Simplifying this:
\[ x + 2 - 8 = 0 \implies x - 6 = 0 \implies x = +6 \]
- The oxidation state of sulfur in H2SO4 is +6, which is its maximum oxidation state.

3. **Determine the Oxidation State of Nitrogen in HNO3**:
- Let the oxidation state of nitrogen be \( x \).
- The equation for HNO3 is:
\[ x + 1 + 3(-2) = 0 \]
- Simplifying this:
\[ x + 1 - 6 = 0 \implies x - 5 = 0 \implies x = +5 \]
- The oxidation state of nitrogen in HNO3 is +5, which is its maximum oxidation state.

4. **Determine the Oxidation State of Manganese in KMnO4**:
- Let the oxidation state of manganese be \( x \).
- The equation for KMnO4 is:
\[ x + 1 + 4(-2) = 0 \]
- Simplifying this:
\[ x + 1 - 8 = 0 \implies x - 7 = 0 \implies x = +7 \]
- The oxidation state of manganese in KMnO4 is +7, which is its maximum oxidation state.

5. **Determine the Oxidation State of Chromium in K2Cr2O7**:
- Let the oxidation state of chromium be \( x \).
- The equation for K2Cr2O7 is:
\[ 2x + 2(+1) + 7(-2) = 0 \]
- Simplifying this:
\[ 2x + 2 - 14 = 0 \implies 2x - 12 = 0 \implies 2x = +12 \implies x = +6 \]
- The oxidation state of chromium in K2Cr2O7 is +6, which is its maximum oxidation state.

6. **Conclusion**:
- In all the compounds, the central atoms (sulfur, nitrogen, manganese, and chromium) are in their maximum oxidation states. Therefore, they cannot be oxidized further.
- Since these species can accept electrons and get reduced, they act as oxidizing agents.

### Final Answer:
All the given compounds (H2SO4, HNO3, KMnO4, K2Cr2O7) can act as oxidizing agents.