26) Balloons are filled with
A. nitrogen
B. helium
C. oxygen
D. argon
Click Here to Reveal Answer
Answer Option B
27) Which metal pollute the air of a big city?
A. Copper
B. Chromium
C. Lead
D. Cadmium
Click Here to Reveal Answer
Answer Option C
28) Water is a good solvent of ionic salts because
A. it has a high specific heat
B. it has no colour
C. it has a high dipole moment
D. it has a high boiling point
Click Here to Reveal Answer
Answer Option C
29) The main constituents of pearls are
A. calcium oxide and ammonium chloride
B. calcium carbonate and magnesium carbonate
C. aragonite and conchiolin
D. ammonium sulphate and sodium carbonate
Click Here to Reveal Answer
Answer Option B
30) Which of the following is the lightest metal?
A. Mercury
B. Lithium
C. Lead
D. Silver
Click Here to Reveal Answer
Answer Option B
 Questions in Competitive Examinations){kind=link}