Q1: Fusion zone in the electric furnace used for reduction of phosphate rock to elemental phosphorous is maintained at __________ °C.

ANS:D - 1400-1450

Maintaining the fusion zone in the electric furnace at temperatures around 1400-1450°C would not be accurate for the reduction of phosphate rock to elemental phosphorus. The fusion zone temperature in this range is typically too high for this specific process. However, temperatures in this range are commonly associated with other high-temperature processes such as metal smelting, glassmaking, or certain types of ceramic production. In these processes, such high temperatures are necessary to melt or fuse raw materials, facilitate chemical reactions, and achieve the desired product properties. For the reduction of phosphate rock to elemental phosphorus, the fusion zone temperature is typically lower, around 950-1050°C. At this temperature range, phosphate rock reacts with carbon (usually in the form of coke) in an electric furnace, undergoing reduction to elemental phosphorus vapor and carbon monoxide gas. The high temperature is sufficient to promote the reaction while avoiding excessive energy consumption or equipment damage.