Complete the following statements by selecting the correct alternative from the choices given :
Purification of aluminium by electrolytic refining is called :

Options

A. Serpeck's process
B. Hoope's process
C. Hall's process
D. Baeyer's process

Explanation

To solve the question, we need to identify the correct term used for the purification of aluminum through electrolytic refining. Here’s a step-by-step solution:

### Step 1: Understand the Process
The question asks about the purification of aluminum by electrolytic refining. This process is commonly used to obtain pure aluminum from its ores.

**Hint:** Think about the common methods used for purifying metals, especially aluminum.

### Step 2: Identify the Options
The options provided are:
1. Pex process
2. Hoops process
3. Halls process
4. Bare process

**Hint:** Review the names of the processes and see if any are specifically associated with aluminum.

### Step 3: Recall the Correct Process
Among the options, the process specifically known for the electrolytic refining of aluminum is the "Halls process." This process is named after Charles Martin Hall, who developed it.

**Hint:** Consider the historical context of aluminum purification and the names associated with it.

### Step 4: Confirm the Correct Answer
The correct answer to the question is the "Halls process," which is option 3. This process allows for the extraction of aluminum with a high degree of purity, typically around 99.9%.

**Hint:** Verify your answer by recalling the details of the Halls process and its significance in aluminum production.

### Final Answer
Purification of aluminum by electrolytic refining is called the **Halls process**.