Consider the following steps:
`Cu_(2)S overset("roast in air")rarr A overset("Heating without air")rarr B` Which is not the correct statement:

Options

A. it is self-reduction
B. A is only `Cu_(2)O & B` is a mixture of `Cu & SO_(3)`
C. A is a mixture of `Cu_(2)O` and `Cu_(2)S` and `B` is a mixture of `Cu & SO_(2)`
D. all are incorrect statements

Answer

To solve the question regarding the roasting of Cu₂S and the subsequent heating without air, we can break down the process step by step.

### Step 1: Understanding the Roasting of Cu₂S
When Cu₂S (copper(I) sulfide) is roasted in air, it undergoes a chemical reaction where it is converted to its oxide form. The reaction can be represented as follows:

\[ \text{Cu}_2\text{S} + \text{O}_2 \rightarrow \text{Cu}_2\text{O} + \text{SO}_2 \]

In this reaction:
- Cu₂S reacts with oxygen (O₂) from the air.
- The products formed are Cu₂O (cuprous oxide) and SO₂ (sulfur dioxide).

### Step 2: Identifying the Product A
From the roasting process, we can conclude that the product A formed is:
- A = Cu₂O + SO₂

### Step 3: Heating Without Air
After the roasting process, the next step involves heating the product without air. This process is known as self-reduction. In this step, the remaining Cu₂S reacts with Cu₂O. The reaction can be represented as follows:

\[ \text{Cu}_2\text{O} + \text{Cu}_2\text{S} \rightarrow 6 \text{Cu} + \text{SO}_2 \]

### Step 4: Identifying the Product B
From the self-reduction process, we can conclude that the product B formed is:
- B = Cu (metallic copper) + SO₂

### Step 5: Analyzing the Statements
Now, we need to determine which statement is incorrect based on the information we have gathered:
1. A is a mixture of Cu₂O and SO₂.
2. B is a mixture of Cu and SO₂.
3. The self-reduction process does not require an external reducing agent.
4. A is only Cu₂O (this statement is incorrect because A also contains SO₂).

### Conclusion
The incorrect statement is:
- "A is only Cu₂O" because A actually consists of both Cu₂O and SO₂.