Related Questions

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
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
Maximum stability of white phosphorous is at
A Very high pressure
B Atmospheric pressure
C Room temperature
D >600°C
একটি থলেতে 4 টি সাদা এবং 2 টি কালো বল আছে। অপর একটি থলেতে 3 টি সাদা ও 5 টি কালো বল আছে। যদি প্রত্যেক থলে হতে একটি করে বল উত্তোলন করা হয়, তবে বলদ্বয় সাদা হওয়ার সম্ভাবনা কত? (A bag contains 4 white and 2 black balls. Another bag contains 3 white and 5 black balls. If one ball is drawn from each bag, what is the probability that both balls are white?)
A 4/6
B 3/8
C 1/4
D 3/4
Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes
A Foaming
B Odour nuisances
C Undesirable plant growth
D Turbidity
The molecular formula of phosphorous is
A P1
B P2
C P3
D P4
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

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