A. Heating in presence of light
B. Melting under pressure
C. Vaporisation followed by condensation
D. None of these
Related Mcqs:
- Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at ____________ °C in absence of air?
A. 50-80
B. 250-400
C. 1000-1200
D. 800-900 - Conversion of yellow phosphorus to red phosphorous is done in retorts at 250-450°C in the ___________________?
A. Presence of an inert atmosphere
B. Presence of a reducing atmosphere
C. Absence of air
D. Presence of an oxidising atmosphere - Both white phosphorous as well as red phosphorous_________________?
A. Are soluble in CS2
B. Burns when heated in air
C. Reacts with hot caustic soda solution to give Phosphine
D. All A., B., and C. - Electric furnace method for production of phosphorous uses phosphate rock and _________________________?
A. Phosphoric acid
B. Coke
C. Sulphuric acid
D. Silica and coke - A mixture of phosphate rock ______________ is heated in an electric furnace to produce phosphorous?
A. Salt & coke
B. Sand & coke
C. And coke
D. And sand - Maximum stability of white phosphorous is at__________________?
A. Very high pressure
B. Atmospheric pressure
C. Room temperature
D. > 600°C - Yield of elemental phosphorous from rock phosphate is about _____________ percent?
A. 1-2
B. 15-25
C. 40-45
D. 60-65 - Fusion zone in the electric furnace used for reduction of phosphate rock to elemental phosphorous is maintained at ______________ °C?
A. 250-300
B. 500-750
C. 950-1050
D. 1400-1450 - Which one of the following is used as a nitrogenous fertiliser, as a weed killer in the onion fields and for correcting acidic soils ?
A. Urea
B. CAN
C. Ammonium sulphate
D. Calcium cyanamide - Commercial production of hydrogen for the manufacture of nitrogenous fertilisers is done by________________?
A. Steam reforming of naphtha and cracking of natural gas
B. Electrolysis of water
C. Cryogenic separation of hydrogen from coke oven gas
D. All A., B. and C.
