• Chemistry - Section 1
71. 

The molecular formula of phosphorous is

A. P1
B.

P2

C.

P3

D.

P4


72. 

The inert gases are ____ in water

A. sparingly soluble
B.

अघुलनशील

C.

घुलनशील

D.

इनमे से कोई नहीं 


73. 

The method of concentrating the ore which makes use of the difference in density between ore and impurities is called

A. liquation
B.

लीचिंग

C.

लेविगेशन 

D.

चुंबकीय जुदाई


74. 

The metal that is usually extracted from sea water is

A. Ca
B.

Na

C.

K

D.

Mg


75. 

The names of the scientists, Newlands, Mendeleev, and Meyer are associated with the development of

A. atomic structure
B.

धातुकर्म

C.

सामग्री की आवधिक तालिका

D.

तत्वों की खोज