Lead obtained from galena ore `(PbS)` by air reduction or carbon reduction process contains base metal `(cu, Bi, As, Sn,Zn)` as impurities.
Gelatin acts as addition agent in electrolysis of `Pb`. In the presence of gelatin, `Pb` becomes.

Options

A. Hard and brittle
B. Soft and useless
C. Smooth and uniform
D. Only brittle

Answer

To solve the question regarding the role of gelatin in the electrolysis of lead obtained from galena ore (PbS), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**:
- Lead is extracted from galena (PbS) through reduction processes which may leave behind impurities such as copper (Cu), bismuth (Bi), arsenic (As), tin (Sn), and zinc (Zn).
- These impurities can affect the quality of the lead produced.

2. **Identifying the Purpose of Electrolysis**:
- Electrolysis is used to purify lead. During this process, the aim is to obtain smooth and high-quality lead by removing the impurities.

3. **Role of Gelatin**:
- Gelatin is added as an additive during the electrolysis of lead. The presence of gelatin plays a crucial role in the electrolysis process.

4. **Effects of Gelatin on Lead**:
- When gelatin is added to the electrolyte (which typically consists of PbSiF6 and H2SiF6), it helps in the uniform deposition of lead on the cathode.
- This uniform deposition is essential for producing smooth lead, which is desirable for its applications, such as in batteries.

5. **Conclusion**:
- In the presence of gelatin, lead becomes smooth and uniform due to the controlled deposition facilitated by the gelatin.

### Final Answer:
In the presence of gelatin, lead becomes smooth and uniform.