36. Which of the following was to be discovered first in the chromospheres of the sun?
A. Krypton
B. Xenon
C. Neon
D. Helium
37. Which of the following is in liquid form at room temperature?
A. Lithium
B. Sodium
C. Francium
D. Cerium
38. Sodium metal is kept under
A. petrol
B. alcohol
C. water
D. kerosene
39. Which of the following are the ingredients of gun metal?
A. Iron, Zinc, Titanium
B. Iron, tin
C. Iron, Brass, Tin
D. Copper, Tin
40. From which mineral is radium obtained?
A. Rutile
B. Haematite
C. Limestone
D. Pitchblende