Question

Using which of the following processes, $Zr{I_4}$ is converted to $Zr$?
A. Monds
B. Van Arkel
C. Hall
D. Kroll

Answer 1

Hint:As we know that Zirconium iodide is the most easily available iodide of Zirconium and the pure metal is collected using the decomposition of zirconium iodide to zirconium and two molecules of iodine which were used as a specific reagent in the process at a temperature of about \[2070K\].

Complete answer:
As we know that Zirconium in it impure form is a solid which can be reacted with two molecules of gaseous iodine used as a specific reagent at a temperature of $870K$ which results in the formation of gaseous volatile zirconium iodide. Now this zirconium iodide is subjected to electrical decomposition on a white hot tungsten filament at a temperature of \[2070K\] and it results in the formation of ultrapure zirconium metal and releases two molecules of iodine into the solution. This process of getting an ultrapure metal is known as Van Arkel Method.
We can show this through an equation:
$Zr(impure) + 2{I_2}(g)\xrightarrow{{870K}}Zr{I_4}(volatile)$
$Zr{I_2}(g)\xrightarrow[{at\;filament}]{{2070K}}Zr(pure) + 2{I_2}$

Therefore the correct answer is Option 2.

Additional information:
Similarly, titanium can also be obtained as pure metal under the same method. Zirconium is highly ductile and malleable metal, it along with zirconium iodide are found in pipes fittings and heat exchangers as well as used in steel alloys, bricks, ceramics, flash bulbs, lamp filaments etc. because it can tolerate high temperatures and are strong.

Note:
Van Arkel method is also known as Crystal bar method or Iodide process because iodine has the capability to form tetraiodide volatile salts of impure metals which is then decomposed to get an ultrapure metal. But zirconium is radioactive and an irritant at low levels which is toxic to human beings.