MolSynapsequestion bank
MolSynapse / Question bank / Metallurgy / Refining methods: zone refining, van Arkel, Mond process, electrolytic refining
JEE Advanced levelSingle correct optionDifficulty 3 of 3mt187

For , take and , independent of temperature. The values of at 330 K and at 460 K, and what they imply for the Mond process, are

  1. A-160.9 kJ at 330 K and -160.8 kJ at 460 K; carbonyl is stable at both temperatures
  2. B-30.3 kJ at 330 K and +21.2 kJ at 460 K; carbonyl forms at the lower temperature and decomposes at the higher temperature
  3. C+30.3 kJ at 330 K and -21.2 kJ at 460 K; carbonyl forms at the higher temperature
  4. D-291.7 kJ at 330 K and -343.2 kJ at 460 K; carbonyl is stable at both temperatures

Answer: B

. At 330 K: kJ (forward spontaneous). At 460 K: kJ (reverse spontaneous). The change of sign occurs at 407 K, consistent with forming the carbonyl at 330-350 K and decomposing it at 450-470 K.
Practice Metallurgy More on Refining methods: zone refining, van Arkel, Mond process, electrolytic refining

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