Lead is not affected by dil . HCl in cold , because

Options

A. Pb is less electronegative than H
B. PbO film is formed which resists chemical attack by acid.
C. A protective coating of `PbCl_2` is formed on Pb surface
D. `PbO_2`of film is always present on Pb surface , which resists chemical attack

Answer

To solve the question "Lead is not affected by dilute HCl in cold, because...", we need to analyze the behavior of lead when it comes into contact with dilute hydrochloric acid (HCl). Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understanding the Reaction
When lead (Pb) is exposed to dilute HCl, a chemical reaction can occur. The expected products of this reaction are lead(II) chloride (PbCl2) and hydrogen gas (H2).

### Step 2: Formation of Protective Coating
During the reaction, lead(II) chloride (PbCl2) is formed. This compound is not very soluble in water and tends to precipitate out of the solution, forming a solid layer or coating on the surface of the lead.

### Step 3: Effect of the Coating
This solid coating of PbCl2 acts as a protective barrier. It prevents further contact between the lead and the dilute HCl, effectively stopping any additional reaction from occurring. As a result, the lead does not get corroded or affected by the acid in cold conditions.

### Step 4: Evaluating the Options
Now, let’s evaluate the options provided in the question:
1. **Pb is less electronegative than H**: This is true, but it does not explain why lead is not affected by HCl.
2. **PbO film is formed**: This is incorrect, as PbO is not formed in this scenario.
3. **Protective coating of PbCl2 is formed on Pb surface**: This is correct and explains why lead is not affected.
4. **PbO2 film is always present**: This is incorrect, as PbO2 is not relevant in this context.

### Conclusion
The correct reason why lead is not affected by dilute HCl in cold is due to the formation of a protective coating of PbCl2 on the surface of the lead.

### Final Answer
Lead is not affected by dilute HCl in cold because a protective coating of PbCl2 is formed on the surface of the lead.

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