Elements And Metals : 1

Question 16 :

The inert gas which is substituted for nitrogen in the air used by deep sea divers for breathing, is

A). Argon
B). Xenon
C). Helium
D). Krypton
Answer : Option C

Question 17 :

The gases used in different types of welding would include

A). oxygen and hydrogen
B). oxygen, hydrogen, acetylene and nitrogen
C). oxygen, acetylene and argon
D). oxygen and acetylene
Answer : Option D

Question 18 :

The property of a substance to absorb moisture from the air on exposure is called

A). osmosis
B). deliquescence
C). efflorescence
D). desiccation
Answer : Option B

Question 19 :

In which of the following activities silicon carbide is used?

A). Making cement and glass
B). Disinfecting water of ponds
C). cutting very hard substances
D). Making casts for statues
Answer : Option C

Question 20 :

The average salinity of sea water is

A). 3%
B). 3.5%
C). 2.5%
D). 2%
Answer : Option B