MolSynapsequestion bank
MolSynapse / Question bank / Metallurgy / Refining methods: zone refining, van Arkel, Mond process, electrolytic refining
JEE Advanced levelOne or more correct optionsDifficulty 3 of 3mt190

For a metal to be refined by a vapour-phase (Mond or van Arkel type) method, which conditions must hold?

  1. AThe volatile compound must decompose at a higher temperature to regenerate the metal
  2. BThe impurities must not form volatile compounds with the reagent under those conditions
  3. CFormation of the compound must be more favourable at the higher decomposition temperature
  4. DThe metal must form a volatile compound with the reagent at a moderate temperature

Answer: A, B, D

Such methods need a volatile compound that forms readily at moderate temperature, leaves the impurities behind, and decomposes at a higher temperature to give pure metal. Formation is exothermic with a fall in entropy, so it is favoured at lower, not higher, temperature.
Practice Metallurgy More on Refining methods: zone refining, van Arkel, Mond process, electrolytic refining
Previous questionNext question

More questions on Refining methods: zone refining, van Arkel, Mond process, electrolytic refining