1. 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
Explanation: Silicon carbide is used in cutting very hard substances.
2. The average salinity of seawater is
a) 3%
b) 3.5%
c) 2.5%
d) 2%
Explanation: Salinity is generally low at the equator and at the poles, and high at mid-latitudes. The average salinity is about 35 parts per thousand. Stated in another way, about 3.5 percent of the weight of seawater comes from the dissolved salts.
3. When an iron nail gets rusted, iron oxide is formed
a) Without any change in the weight of the nail
b) With decrease in the weight of the nail
c) With increase in the weight of the nail
d) Without any change in colour or weight of the nail
Explanation: When an iron nail gets rusted, iron oxide is formed with increase in the weight of the nail.
4. Galvanised iron sheets have a coating of
a) Lead
b) Chromium
c) Zinc
d) Tin
Explanation: Galvanization is the process of applying a protective zinc coating to steel or iron in order to prevent it from rusting.
5. Among the various allotrope of carbon
a) Coke is the hardest, graphite is the softest
b) Diamond is the hardest, coke is the softest
c) Diamond is the hardest, graphite is the softest
d) Diamond is the hardest, lamp black is the softest
Explanation: Among the various allotrope of carbon diamond is the hardest, graphite is the softest.
6.LPG consists of mainly:
a) Methane, Ethane and Hexane
b) Ethane, Hexane and Nonane
c) Methane, Hexane and Nonane
d) Methane, Butane and Propane
Explanation: Liquefied Petroleum Gas or LPG consists mainly of methane, propane, propylene, butane, and butylene in various mixtures. It is produced as a by-product of natural gas processing and petroleum refining. The components of LPG are gases at normal temperatures and pressures.
7. Air is a/an:
a) Compound
b) Element
c) Electrolyte
d) Mixture
Explanation:Air is a mixture because we can separate its components while in compound we can not separate it.
8. Production of chlorofluorocarbons (CFC) gas which is proposed to be banned in India, is used in which of the following domestic products?
a) Television
b) Refrigerator
c) Tube light
d) Cooking gas
Explanation: Production of chlorofluorocarbons (CFC) gas which is proposed to be banned in India, is used in refrigerator.
9. Balloons are filled with
a) Nitrogen
b) Helium
c) Oxygen
d) Argon
Explanation: A balloon is a flexible bag that can be inflated with a gas, such as helium, hydrogen, nitrous oxide, oxygen, and air.
10. Which of the following does not contain a coinage metal?
a) Silver and Gold
b) Zinc and Gold
c) Copper and Silver
d) Copper and Gold
Explanation: Zinc and Gold does not contain a coinage metal.