`(Ag +Pb) alloy overset("Melt and add zinc")rarr (Ag +Pb +Zn) "melt" overset("Cool") rarr (LayerX)/(LayerY)`
Select correct statements based on above scheme:

Options

A. Layer X contains zinc and silver
B. Layer Y contains lead and silver but amount of silver in this layer is smaller than in the layer X
C. X and Y are immicible layers
D. All are correct statements

Answer

To solve the question regarding the alloy of silver (Ag) and lead (Pb) with the addition of zinc (Zn), we will follow the steps outlined in the video transcript and elaborate on the reasoning behind each step.

### Step-by-Step Solution:

1. **Understanding the Initial Alloy**:
- We start with an alloy of silver (Ag) and lead (Pb). This alloy is referred to as argentiferous lead, which contains a small percentage of silver (0.01 to 1% Ag).

**Hint**: Recognize that argentiferous lead is a lead alloy that contains silver.

2. **Melting and Adding Zinc**:
- The alloy is melted, and zinc is added. This forms a new melt comprising Ag, Pb, and Zn. The addition of zinc is crucial as it helps in the separation of silver from lead.

**Hint**: Remember that the melting process allows for the mixing of metals, which is essential for the subsequent separation.

3. **Cooling the Melt**:
- After the zinc is added, the mixture is cooled. This cooling process leads to the formation of two distinct layers due to the different solubilities of the metals involved.

**Hint**: Cooling causes different metals to solidify at different rates, leading to stratification.

4. **Formation of Layers**:
- Upon cooling, two layers are formed:
- **Layer X**: This is the upper layer, which consists of a zinc-silver alloy (ZnAg). Silver is more soluble in molten zinc than in molten lead, so it preferentially moves into the zinc layer.
- **Layer Y**: This is the lower layer, which contains lead (Pb) with small amounts of silver remaining in it.

**Hint**: Understand that the solubility of silver in zinc leads to its concentration in the upper layer.

5. **Properties of the Layers**:
- The ZnAg alloy (Layer X) is lighter than lead and solidifies faster, allowing it to float on top of the molten lead (Layer Y). The two layers are immiscible, meaning they do not mix.

**Hint**: Recall that immiscibility leads to the formation of distinct layers in a mixture.

6. **Separation of Zinc**:
- Finally, the zinc can be separated from the ZnAg alloy through distillation, as it has a lower boiling point compared to silver.

**Hint**: Distillation is a common method for separating components based on their boiling points.

### Conclusion:
Based on the above reasoning, we can conclude that:
- Layer X is the ZnAg alloy (upper layer).
- Layer Y contains lead with some residual silver.
- Both layers are immiscible.

### Correct Statements:
From the analysis, we can affirm that all the statements regarding the process and the layers formed are correct. Therefore, the answer to the question is that all options are correct.

**Final Answer**: All the statements are correct (Option 4).