1. Tetraethyl lead is used as
a) Pain Killer
b) Fire Extinguisher
c) Mosquito Repellent
d) Petrol Additive
Explanation: Tetraethyl lead is used as Petrol Additive.
2. Which of the following is used as a lubricant?
c) Iron Oxide
Explanation: Graphite is structurally composed of planes of polycyclic carbon atoms that are hexagonal in orientation. The distance of carbon atoms between planes is longer and therefore the bonding is weaker. Graphite is best suited for lubrication in air.
It is a mineral made of loosely bonded sheets of carbon atoms, giving it a slippery texture that makes it a very effective lubricant. This slippery quality also makes graphite a good material for pencil lead because it easily sloughs off onto paper.
Graphite is bonded by covalent bond, thus, it is helf by weak intermolecular forces. Since it has weak intermolecular forces, graphite would be slippery and soft enough to act as a lubricant.
3. The inert gas which is substituted for nitrogen in the air used by deep sea divers for breathing, is
Explanation: The inert gas which is substituted for nitrogen in the air used by deep sea divers for breathing, is Helium.
4. 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
Explanation: The gases used in different types of welding would include Oxygen and Acetylene.
5. The property of a substance to absorb moisture from the air on exposure is called
Explanation: Deliquescence, the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution.
6. Which metal pollute the air of a big city?
Explanation: Major sources of lead emissions to the air today are ore and metals processing and piston-engine aircraft operating on leaded aviation gasoline. The highest air concentrations of lead are usually found near lead smelters
7. Bell metal is an alloy of
a) Nickel and Copper
b) Zinc and Copper
c) Brass and Nickel
d) Tin and Copper
Explanation: Bronze used for making bells and gongs is essentially an alloy of copper and tin
8.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
Explanation: It has a high dipole moment
9. Which of the following is not an isotope of hydrogen?
Explanation: Yttrium is not an isotope of hydrogen
10. 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
Explanation: The main constituents of pearls are Calcium Carbonate and Magnesium Carbonate.