Related Questions

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
The most stable allotropic form of phosphorous is the __________ phosphorous.
A White
B Black
C Yellow
D Red
Red phosphorous is changed into white phosphorous by
A Heating in presence of light
B Melting under pressure
C Vaporisation followed by condensation
D None of these
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 of the above
Most of the phosphorous present in the blast furnace burden enters into
A Hot metal
B Flue gases
C Slag
D Refractory lining
Yield of elemental phosphorous from rock phosphate is about __________ percent.
A 1-2
B 15-25
C 40-45
D 60-65
Electric furnace method for production of phosphorous uses phosphate rock
A And phosphoric acid
B And coke
C And sulphuric acid
D Silica and coke
Phosphorous is added to copper melt to
A remove hydrogen
B deoxidise the me
C improve fluidity
D reduce shrinkage
Which of the following is caused by the higher concentration of Nitrogen and Phosphorous ?
A Eutrophication
B Hardness
C Alkalinity
D Acidity
White phosphorous is stored under water, because
A It does not react with water
B It is poisonous
C Its kindling temperature in dry air is very low
D It is unstable

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