General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
41. Cream gets separated out of milk when it is churned due to which of the following reasons?
[A] Gravitational pull
[B] Centripetal force
[C] Centrifugal force
[D] Frictional force
Show Answer
Correct Answer: C [Centrifugal force]
Notes:
When Milk is churned vigorously the cream from it is separated out due to Centrifugal Force. Churning physically agitates the cream until it ruptures the fragile membranes surrounding the milk fat.
42. Which of the following gases is heavier than oxygen?
[A] Ammonia
[B] Methane
[C] Helium
[D] Carbon dioxide
Show Answer
Correct Answer: D [Carbon dioxide]
Notes:
Carbon dioxide has one carbon atom and two oxygen atoms, and a molecular weight of 44 grams per mole. The oxygen in the air is actually O2, or molecular oxygen, with a molecular weight of 32. Hence, carbon dioxide has a higher density, or is heavier than oxygen.
43. Which of the following metals (shown by its symbol) is generally used for making filaments of bulb?
Show Answer
Correct Answer: D [W]
Notes:
Tungsten (W) is used for making the filaments of electric bulbs. The filaments of electric bulb is made with Tungsten (W). No alloy is used as filament of bulb, pure Tungsten is used, because it has higher resistance and higher melting point.
44. Who invented Bakelite, which is one of the first commercially successful plastics of the world?
[A] Leo Baekeland
[B] Otto Bayer
[C] Arthur W. Carpenter
[D] Jean-Baptiste Donnet
Show Answer
Correct Answer: A [Leo Baekeland]
Notes:
Leo Hendrik Baekeland (1863 – 1944) was a Belgian chemist, best known for the inventions of Velox photographic paper in 1893 and Bakelite in 1907. He has been called “The Father of the Plastics Industry” for his invention of Bakelite.
45. Who was the first person to devise a periodic table of chemical elements arranged in order of their relative atomic masses?
[A] Dmitri Mendeleev
[B] John Dalton
[C] John Alexander Reina Newlands
[D] Johann Wolfgang Dobereiner
Show Answer
Correct Answer: C [John Alexander Reina Newlands]
Notes:
John Newlands, a British chemist, was the first person to devise a periodic table of chemical elements arranged in order of their relative atomic masses.
46. Which of the following isotope of Hydrogen has only one neutron?
[A] Protium
[B] Deuterium
[C] Tritium
[D] None of them
Show Answer
Correct Answer: B [Deuterium]
Notes:
99.985% of hydrogen atoms contain only one proton. This isotope is called protium( 1H1). Rest of the percentage of hydrogen atom contains two other isotopes, the one containing 1 proton and 1 neutron is called deuterium (1D2, 0.015%) and the other one possessing 1 proton and 2 neutrons is called tritium (1T3 ). The latter isotope is found in trace amounts on the earth.
47. When a gas ‘X’ reacts with lime water, a compound ‘Y’ is formed. If both X and Y are used as a bleaching agent in chemical industry, then X is__ ?
[A] Ozone
[B] Chlorine
[C] Fluorine
[D] Methane
Show Answer
Correct Answer: B [Chlorine]
Notes:
Chlorine is used as bleaching agent in chemical industries. Thus, X is chlorine gas and Y is bleaching powder (CaOCl2).
48. “Petroleum” can be categorised under which one of the following terms?
[A] Elements
[B] Hydrocarbons
[C] Polymers
[D] Salts
Show Answer
Correct Answer: B [Hydrocarbons ]
Notes:
Petroleum, a complex mixture of hydrocarbons that occur in Earth in liquid, gaseous, or solid form. The term is often restricted to the liquid form, commonly called crude oil, but, as a technical term, petroleum also includes natural gas and the viscous or solid form known as bitumen, which is found in tar sands. The liquid and gaseous phases of petroleum constitute the most important of the primary fossil fuels. Liquid and gaseous hydrocarbons are so intimately associated in nature that it has become customary to shorten the expression “petroleum and natural gas” to “petroleum” when referring to both.
49. Which is the main source of Naphthalene?
[A] Charcoal
[B] Camphor
[C] Coal-tar
[D] Titanium
Show Answer
Correct Answer: C [Coal-tar ]
Notes:
Naphthalene is obtained from either coal tar or petroleum distillation. Naphthalene is derived from a kind of naphtha which is a broad term encompassing any volatile, namable liquid hydrocarbon mixture, including coal tar. It is also produced when things burn, so naphthalene is found in cigarette smoke, car exhaust, and smoke from forest fires. It is used as an insecticide and pest repellent. Naphthalene was first registered as a pesticide in the United States in 1948.
50. What kind of fertilizer is Urea?
[A] Sodium fertilizer
[B] Phosphatic fertilizer
[C] Nitrogenous fertilizer
[D] Potassium fertilizer
Show Answer
Correct Answer: C [Nitrogenous fertilizer]
Notes:Fertilizers provide three primary nutrients: Nitrogen (N), Phosphorus (P) and Potassium (K). Nitrogen supports vegetative growth. Phosphorus improves roots and flowering. Potassium strengthens resistance to environmental assaults, from extreme temperatures to pest attacks. Urea is the most important nitrogenous fertilizer in the market, with the highest Nitrogen content (about 46 per cent). It is a white crystalline organic chemical compound. Urea is neutral in pH and can adapt to almost all kinds of soils. It is a waste product formed naturally by metabolizing protein in humans as well as other mammals, amphibians and some fish. Urea is widely used in the agricultural sector both as a fertilizer and animal feed additive. More than 90% of world production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use.
