Question

Which method of purification is used for refining titanium?

• A. Zone refining
• B. Van Arkel method
• C. Mond process
• D. Liquation

Hint:

Remember the important refining methods:

• Van Arkel Process $\rightarrow$ Titanium, Zirconium

• Mond Process $\rightarrow$ Nickel

• Zone Refining $\rightarrow$ Silicon, Germanium

• Liquation $\rightarrow$ Tin, Lead
A common exam question is to match metals with their purification methods, so memorizing these standard pairs is very useful.

Answer 1

The Correct Option is B

Step 1: Recall the goal of refining.
After extraction, a metal still has impurities. Refining cleans it. Different metals use different refining methods based on their properties.
Step 2: Recall the Van Arkel idea.
The Van Arkel (iodide) method purifies titanium and zirconium. It works by making a volatile metal iodide and then breaking it back into pure metal.
Step 3: Form the volatile iodide.
Impure titanium is heated with iodine: \[ Ti + 2I_2 \rightarrow TiI_4. \] The $TiI_4$ vapour separates from the solid impurities.
Step 4: Decompose the iodide.
The vapour passes over a hot tungsten filament and breaks apart: \[ TiI_4 \rightarrow Ti + 2I_2. \] Pure titanium deposits on the filament and the iodine is reused.
Step 5: Reject the other methods.
Zone refining is for semiconductors like silicon. The Mond process refines nickel using $Ni(CO)_4$. Liquation is for low melting metals like tin. None of these are used for titanium.
Step 6: State the method.
Titanium is refined by the \[ \boxed{\text{Van Arkel method}} \]