Which method of purification is represented by the following equation.
`Ni + 4CO underset(Delta)overset(70^@C)(rarr) Ni(CO_4) underset(Delta)overset(180^@C)(rarr)Ni + 4 CO`

Options

A. Van arkel process
B. zone refining
C. Mond's process
D. Cuppellation

Answer

To determine the method of purification represented by the given equation, we will analyze the chemical reactions step by step.

### Step 1: Identify the Reactants and Products
The equation provided is:
\[ \text{Ni} + 4 \text{CO} \xrightarrow{\Delta, 70^\circ C} \text{Ni(CO}_4\text{)} \xrightarrow{\Delta, 180^\circ C} \text{Ni} + 4 \text{CO} \]

Here, nickel (Ni) reacts with carbon monoxide (CO) to form nickel tetracarbonyl (Ni(CO)₄) at a temperature of 70°C. Upon further heating to 180°C, nickel tetracarbonyl decomposes back to nickel and carbon monoxide.

### Step 2: Understand the Process
The formation of nickel tetracarbonyl is a key aspect of this purification method. Nickel tetracarbonyl is a volatile compound, which means it can be separated from non-volatile impurities present in the nickel ore.

### Step 3: Identify the Purification Method
This process is known as **vapor phase refining**, specifically the **Mons process**. In this method, the metal (nickel) is converted into a volatile complex (nickel tetracarbonyl) and then decomposed to recover pure metal.

### Step 4: Conclusion
Thus, the method of purification represented by the given equation is the **Mons process**, which is a type of vapor phase refining used for nickel.

### Final Answer
The purification method represented by the equation is the **Mons process**.

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