Non-metals and their compounds

61.What is the percentage of oxygen in the air approximately?
A. 21 percent
B. 100 percent
C. 1 percent
D. 78 percent
Option”A” is correct
62.Who discovered oxygen?
A. rutherford
B. cavendish
C. Davy
D. Priestley
Option”D” is correct
63.The most abundant element in the earth’s crust is –
A. silicone
B. calcium
C. nitrogen
D. oxygen
Option”D” is correct
64.Which one of the following gases is not a green house gas?
A. CO₂
B. CH₄
C. NO₂
D. O₂
Option”D” is correct
65.Where does the oxygen gas that gives life to humans come from?
A. Carbon dioxide
B. in water
C. oxides of metals
D. carbonates absorbed from the ground
Option”B” is correct
66.Which mixture of gases do divers use for breathing?
A. oxygen and nitrogen
B. oxygen and hydrogen
C. oxygen and helium
D. oxygen and argon
Option”C” is correct
67.Which of the following is helpful in burning?
A. oxygen
B. hydrogen
C. nitrogen
D. Carbon dioxide
Option”A” is correct
68.The oxygen used for artificial respiration in hospitals is a mixture of the following gases:
A. oxygen and helium
B. nitrogen and argon
C. oxygen and argon
D. oxygen and carbon dioxide
Option”A” is correct
69.On carrying a stick burning in oxygen gas, it –
A. she will extinguish
B. it extinguishes and the gas starts burning
C. it burns fast
D. both that and the gas start burning
Option”C” is correct
70.Which element is found in the largest quantity in the human body?
A. hydrogen
B. nitrogen
C. Carbon
D. oxygen
Option”D” is correct