Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
41. Which of the following is not soluble in water?
[A] Lead Sulphate
[B] Zinc sulphate
[C] Potassium sulphate
[D] Sodium sulphate
Show Answer
Correct Answer: B [Zinc sulphate]
Notes:
Lead sulfate (PbSO4) is a white crystalline solid. It is insoluble in water and sinks in it. It is often seen in the plates/electrodes of car batteries, as it is formed when the battery is discharged.
42. Which of the following molecules or ions involved in the Nitrogen Cycle do not contain oxygen atom?
[A] nitrite
[B] ammonia
[C] nitrate
[D] laughing gas
Show Answer
Correct Answer: B [ammonia]
Notes:
Nitrogen is present in the environment in a wide variety of chemical forms including organic nitrogen, Ammonium (NH4+), nitrite (NO2–), nitrate (NO3–), nitrous oxide (N2O), Nitric oxide (NO) or inorganic nitrogen gas (N2). For organisms to use atmospheric nitrogen (N2), it must be “fixed” or converted into ammonia (NH3).The processes of the nitrogen cycle transform nitrogen from one form to another. It involves nitrification, the conversion of ammonia (NH3) to nitrate (NO3–). Ammonia does not contain oxygen.
43. The heat value of combustion of Gasoline is:
[A] 12600 kJ/kg
[B] 14600 kJ/kg
[C] 39400 kJ/kg
[D] 47000 kJ/kg
Show Answer
Correct Answer: D [47000 kJ/kg]
Notes:
The calorific value of Gasoline is 47,000 kJ/kg. The calorific value of a fuel is the quantity of heat produced by its combustion – at constant pressure and under “normal” conditions (i.e. to 0oC and under a pressure of /atm).
44. The quality of petrol is expressed in terms of:
[A] Cetane number
[B] Gold number
[C] Octane number
[D] Added unlead compounds
Show Answer
Correct Answer: C [Octane number]
Notes:
Octane rating or octane number is a standard measure of the ignition quality of gas (gasoline or petrol). Higher this number, the less susceptible is the gas to ‘knocking’ (explosion caused by its premature burning in the combustion chamber) when burnt in a standard (spark-ignition internal combustion) engine.
45. Which one of the following vegetable oils is used in the manufacture of paints?
[A] Palm oil
[B] Sunflower oil
[C] Linseed oil
[D] Cottonseed oil
Show Answer
Correct Answer: C [Linseed oil]
Notes:
Linseed oil and castor oils are used mainly as drying agents in paints and varnishes. Linseed oil is generally used in the manufacture of oil paints, drying oil finish or varnish in wood finishing, as a pigment binder in oil paints, as a plasticizer and in the manufacture of linoleum.
46. Which of the following gas was released during Bhopal gas tragedy?
[A] Methyl isocyanate
[B] Sodium isothiocyanate
[C] Nitrogen isothiocyanate
[D] Potassium isothiocyanate
Show Answer
Correct Answer: A [Methyl isocyanate]
Notes:
The Bhopal gas tragedy involved the leakage of poisonous methyl isocyanate (MIC) gas and other chemical sat the Union Carbide India Limited pesticide plant in Bhopal, Madhya Pradesh, on 2–3 December 1984. It is considered the world’s worst industrial disaster.
47. Which among the following is true about Rayon?
[A] It is obtained from silk worm
[B] It is obtained from wood pulp
[C] It is obtained from both silk worm and wood pulp
[D] None of the above
Show Answer
Correct Answer: B [It is obtained from wood pulp]
Notes:
Rayon is a natural-based material that is made from the cellulose of wood pulp which is chemically converted into a soluble compound. It is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in fibers of nearly pure cellulose.
48. Which of the following acid found in Apple?
[A] Malic Acid
[B] Nitric Acid
[C] Formic Acid
[D] Sulphuric Acid
Show Answer
Correct Answer: A [Malic Acid]
Notes:
Malic acid is a naturally occurring substance found in many fruits and vegetables, and is largely responsible for the sour taste found in apples and pears. Malic acid was first isolated from apple juice by Carl Wilhelm Scheele in 1785.
49. Who was the first person to isolate methane gas? He discovered that methane mixed with air could be exploded using an electric spark.
[A] Alessandro Volta
[B] William Thomson
[C] Luis Pasteur
[D] William Crookes
Show Answer
Correct Answer: A [Alessandro Volta]
Notes:
Alessandro Volta is cre-dited as the inventor of the electric battery and the discoverer of methane. In 1775 his interest in electri-cityled him to improve the electrophorus, a device used to generate static electricity. He discovered and isolated met-hane gas in 1776. The SI unit of electric potential is named in his honour as the volt.
50. Depleted uranium, a by-product of uranium enrichment can be used:
[A] Fuel for nuclear reactors
[B] To treat cancer
[C] In military weapons
[D] None of the above
Show Answer
Correct Answer: C [In military weapons]
Notes:- Depleted uranium (DU) is a by-product of uranium enrichment.
- Enriched uranium is highly radioactive and is used in nuclear reactors and nuclear weapons.
- In comparison to enriched uranium, depleted uranium is much less radioactive and is incapable of generating a nuclear reaction.
- Due to its high density (more dense than lead), depleted uranium is widely used in weapons as it can easily penetrate armour plating.
- The US began manufacturing armour-piercing rounds with depleted uranium in the 1970s and has since added it to composite tank armour to strengthen it.
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