Molecular seives are regenerated by heating to __________ °C.

ANS:B - 200-330

Molecular sieves are typically regenerated by heating to temperatures in the range of 200-330°C. Regeneration of molecular sieves involves removing the adsorbed molecules from their porous structure, which can be achieved by heating the sieves to temperatures that are sufficiently high to drive off the adsorbed molecules without damaging the molecular sieve material itself. The temperature range of 200-330°C is commonly used for this purpose, as it effectively removes the adsorbed molecules while minimizing the risk of thermal degradation of the molecular sieve material. So, the correct completion is: 200-330°C.