Which of the following metal oxides are reduced by self-reduction method ?

Options

A. `Cu_(2)O`
B. `PbO`
C. `HgO`
D. `CaO`

Answer

To determine which metal oxides are reduced by the self-reduction method, we need to analyze the characteristics of the metals involved and their reactivity. The self-reduction method is typically applicable to metals with medium reactivity, such as copper, lead, and mercury. Here’s a step-by-step solution:

### Step 1: Identify the Metals
First, we need to identify the metals associated with the oxides in question. The common metal oxides that are typically considered for self-reduction include:
- Copper oxide (Cu2O)
- Lead oxide (PbO)
- Mercury oxide (HgO)
- Calcium oxide (CaO)

### Step 2: Classify the Metals
Next, we classify these metals based on their reactivity:
- **Highly Reactive Metals**: Potassium, Sodium, Calcium, Magnesium, Aluminum
- **Medium Reactive Metals**: Copper, Lead, Mercury

### Step 3: Analyze the Self-Reduction Method
The self-reduction method involves a reaction where a metal oxide can reduce itself to a lower oxidation state. For example:
- **Copper Oxide (Cu2O)** can react with sulfur dioxide (SO2) to produce copper sulfide (Cu2S) and regenerate Cu2O.
- **Lead Oxide (PbO)** can similarly undergo reduction.
- **Mercury Oxide (HgO)** can also be reduced in a similar manner.

### Step 4: Exclude Highly Reactive Metals
Calcium oxide (CaO) is associated with calcium, which is a highly reactive metal. Therefore, it does not participate in the self-reduction method.

### Step 5: Conclusion
Based on the analysis, the metal oxides that are reduced by the self-reduction method are:
- Copper oxide (Cu2O)
- Lead oxide (PbO)
- Mercury oxide (HgO)

Thus, the correct answer includes copper, lead, and mercury oxides.

### Final Answer:
The metal oxides that are reduced by the self-reduction method are:
- Copper oxide (Cu2O)
- Lead oxide (PbO)
- Mercury oxide (HgO)