Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at __________ °C in absence of air.

Conversion of yellow phosphorous to red phosphorous is done by heating

1.	Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at __________ °C in absence of air.
A.	800-900
B.	50-80
C.	1000-1200
D.	250-400
Answer» D. 250-400