Question

B can be obtained from halide by van-Arkel method. This involves reaction:
A.$2B{I_3}\xrightarrow[{filament}]{{Red{\text{ }}hot{\text{ }}W{\text{ }}or{\text{ }}Ta}}2B + 3{I_2}$
B.$2BC{l_3} + 3{H_2}\xrightarrow[{filament}]{{Red{\text{ }}hot{\text{ }}W{\text{ }}or{\text{ }}Ta}}2B + 6HCl$
C.Both (A) and (B)
D.None of the above

Answer 1

Van Arkel process involves conversion of impure metal into a volatile compound. Then this volatile compound undergoes decomposition by heating to obtain pure metal on the filament leaving the impurities behind.

Complete answer:
This question deals with the van-Arkel process so first let us see what the van-Arkel process is. The van-Arkel process deals with purification of metals mainly titanium and zirconium. This process is used for obtaining very pure metals but in small quantities.
This is done mainly by decomposition of metal iodide which yields the metal. We can see option A deals with decomposition of metal iodide. Iodine is used to form volatile salt. First metal iodide is formed by combining the impure metal with iodine. Then this metal iodide is heated, which results in decomposition of metal iodide, which gives pure metal and iodine is removed. This process is also known as vapour phase refining. The temperature in this reaction used to heat metal iodide is around $1800K$ . The metal iodide in case of purification of titanium is titanium tetraiodide.
There is no mention of metal chlorides in the process so option B is rejected.

So, option A is the correct answer.

Note:
The Van Arkel process is also known as the crystal bar process. But now this process was succeeded by the Kroll process. The iodine which is formed as a byproduct of the reaction is further used again for the same reaction. The filament used in this reaction is a tungsten filament. The name of this process is followed by its developer Anton Eduard van Arkel. He developed it in 1925.