Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at ____________ °C in absence of air? August 29, 2021March 11, 2019 by admin Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at ____________ °C in absence of air? A. 50-80B. 250-400 C. 1000-1200 D. 800-900