Van Arkel method of purification of metals involves converting the metal to a [BHU 1990]A) Volatile stable compound B) Volatile unstable compound C) Nonvolatile stable compound D) None of the above

Van Arkel method of purification of metals involves converting the met

1.	Van Arkel method of purification of metals involves converting the metal to a [BHU 1990]A) Volatile stable compound B) Volatile unstable compound C) Nonvolatile stable compound D) None of the above
Answer» The CORRECT answer should be the option B - Volatile unstable compound. Van Arkel method is used for purifying METALS like TI and Zn which are then refined. This method is used to obtain ultra-pure metals. It is also CALLED as Vapor Phase refining. The process involves the decomposition of the metal compound into different unstable substances when heat is supplied. This is called as thermal decomposition. The metals are converted into unstable metal IODIDES which decompose easily to form pure metals. Ti + 2I₂ → 500 K + TiI₄ → 1700 K + Ti (Pure metal) + 2I₂