Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
41. Kinetics is the study of:
[A] The rate of chemical reaction
[B] How fast the reactions go
[C] The mechanisms and paths of the molecules take in joining from one reactant to products
[D] All of the above
[B] How fast the reactions go
[C] The mechanisms and paths of the molecules take in joining from one reactant to products
[D] All of the above
Correct Answer: D [All of the above ]
Notes:
In chemistry, the study of rates and mechanisms of chemical processes and, of the factors on which they depend, is called kinetics. It studies of how fast chemical reactions occur. Therefore, it studies provide reaction mechanisms, examining what path the reactants take in order to become the products along with detailed picture of which bonds are broken and formed during the course of a reaction.
In chemistry, the study of rates and mechanisms of chemical processes and, of the factors on which they depend, is called kinetics. It studies of how fast chemical reactions occur. Therefore, it studies provide reaction mechanisms, examining what path the reactants take in order to become the products along with detailed picture of which bonds are broken and formed during the course of a reaction.
42. By which process is ethanol produced?
[A] Salinization
[B] Combination
[C] Titration
[D] Fermentation
[B] Combination
[C] Titration
[D] Fermentation
Correct Answer: D [Fermentation]
Notes:
Ethanol is produced through the process of fermentation, using glucose derived from sugars (sugarcane, sugar beet and molasses), starch (corn, wheat, grains) or cellulose (forest products) as raw materials. During fermentation, sugar is anaerobically converted into ethanol, water, and carbon dioxide.
Ethanol is produced through the process of fermentation, using glucose derived from sugars (sugarcane, sugar beet and molasses), starch (corn, wheat, grains) or cellulose (forest products) as raw materials. During fermentation, sugar is anaerobically converted into ethanol, water, and carbon dioxide.
43. Which of the following is used as fuel rods in Atomic reactor?
[A] Sodium
[B] Uranium
[C] Graphite
[D] Boron
[B] Uranium
[C] Graphite
[D] Boron
Correct Answer: B [Uranium]
Notes:
Under 1% of the uranium found in nature is the easily fissionable U-235 isotope and as a result most reactor designs require enriched fuel. Enrichment involves increasing the percentage of U-235 and is usually done by means of gaseous diffusion or gas centrifuge. The enriched result is then converted into uranium dioxide powder, which is pressed and fired into pellet form. These pellets are stacked into tubes which are then sealed and called fuel rods. Most BWR and PWR commercial reactors use uranium enriched to about 4%.
Under 1% of the uranium found in nature is the easily fissionable U-235 isotope and as a result most reactor designs require enriched fuel. Enrichment involves increasing the percentage of U-235 and is usually done by means of gaseous diffusion or gas centrifuge. The enriched result is then converted into uranium dioxide powder, which is pressed and fired into pellet form. These pellets are stacked into tubes which are then sealed and called fuel rods. Most BWR and PWR commercial reactors use uranium enriched to about 4%.
44. The temperature of oxy-acetylene flame is around:
[A] 2800°C
[B] 3200°C
[C] 4000°C
[D] 1500°C
[B] 3200°C
[C] 4000°C
[D] 1500°C
Correct Answer: B [3200°C]
Notes:
Flames are formed when a fuel gas, like acetylene, reacts with a support gas such as oxygen. This reaction creates a lot of heat and light, which we see as a flame. An oxygen acetylene flame can create temperatures over 3200°C. Pure oxygen, instead of air (20% oxygen/80% nitrogen), is used to increase the flame temperature to allow localized melting of the work piece material (e.g. steel) in a room environment. A common propane/air flame burns at about 3,630 degree F (2,000 degree C), a propane/ oxygen flame burns at about 4,530 degree F (2,500 degree C), and an acetylene/oxygen flame burns at about 6,330 degree F (3,500 degree C).
Flames are formed when a fuel gas, like acetylene, reacts with a support gas such as oxygen. This reaction creates a lot of heat and light, which we see as a flame. An oxygen acetylene flame can create temperatures over 3200°C. Pure oxygen, instead of air (20% oxygen/80% nitrogen), is used to increase the flame temperature to allow localized melting of the work piece material (e.g. steel) in a room environment. A common propane/air flame burns at about 3,630 degree F (2,000 degree C), a propane/ oxygen flame burns at about 4,530 degree F (2,500 degree C), and an acetylene/oxygen flame burns at about 6,330 degree F (3,500 degree C).
45. What happens when a drop of glycerol is added to crushed KMnO4 spread on a paper?
[A] There is a crackling sound.
[B] There is a violent explosion.
[C] There is no reaction.
[D] The paper ignites.
[B] There is a violent explosion.
[C] There is no reaction.
[D] The paper ignites.
Correct Answer: B [There is a violent explosion.]
Notes:
When solid Potassium Permanganate (KMnO4) is mixed with pure glycerol or other simple alcohols, it results in a violent combustion reaction. Potassium Permanganate is an extremely powerful oxidizer which spontaneously ignites after coming in contact with glycerol. The glycerol is oxidized so quickly that heat is generated faster than it can be dissipated.
When solid Potassium Permanganate (KMnO4) is mixed with pure glycerol or other simple alcohols, it results in a violent combustion reaction. Potassium Permanganate is an extremely powerful oxidizer which spontaneously ignites after coming in contact with glycerol. The glycerol is oxidized so quickly that heat is generated faster than it can be dissipated.
- 3C3H5(OH)3 + 14KMnO4 —> 14MnO2 + 7K2CO3 + 2CO2 + 12H2O
46. Which of the following primarily causes lead pollution?
[A] CFL Lamp
[B] Automobile Battery
[C] Polymer
[D] Diesel Engine
[B] Automobile Battery
[C] Polymer
[D] Diesel Engine
Correct Answer: B [Automobile Battery]
Notes:
Lead is a common environmental pollutant. Causes of environmental contamination include industrial use of lead, such as is found in facilities that process lead-acid batteries or produce lead wire or pipes, and metal recycling and foundries. Lead pollution associated with autos gets into the air and soil when lead is produced or recycled for use in cars, and water may be polluted from the disposal of batteries and autos, or when wheel weights are lost on roadways.
Lead is a common environmental pollutant. Causes of environmental contamination include industrial use of lead, such as is found in facilities that process lead-acid batteries or produce lead wire or pipes, and metal recycling and foundries. Lead pollution associated with autos gets into the air and soil when lead is produced or recycled for use in cars, and water may be polluted from the disposal of batteries and autos, or when wheel weights are lost on roadways.
47. Ethylene is a ______ molecule:
[A] polar
[B] ionic
[C] covalent
[D] nonpolar
[B] ionic
[C] covalent
[D] nonpolar
Correct Answer: D [nonpolar]
Notes:
Ethylene (C2H4) is a nonpolar molecule. This is because, unlike a polar molecule, it has an even distribution of electrical charges. Since, the double bond is between two carbon atoms, there is no difference in the electronegativity. This is why, the shared pair of electrons come lie in between those to carbon atoms. As a result, ethylene is a non-polar and linear molecule.
Ethylene (C2H4) is a nonpolar molecule. This is because, unlike a polar molecule, it has an even distribution of electrical charges. Since, the double bond is between two carbon atoms, there is no difference in the electronegativity. This is why, the shared pair of electrons come lie in between those to carbon atoms. As a result, ethylene is a non-polar and linear molecule.
48. Which of the following is not an example of a biomass energy source?
[A] Wood
[B] Gobar gas
[C] Atomic energy
[D] Coal
[B] Gobar gas
[C] Atomic energy
[D] Coal
Correct Answer: C [Atomic energy]
Notes:
Biomass energy is a renewable and sustainable source of energy derived from organic matter and can be used to generate electricity and other forms of power. Common materials that can be used to develop biomass fuel include manure, forest debris, scrap lumber, mulch, sewage, certain crops and some kinds of waste residue. It does not include Atomic energy.
Biomass energy is a renewable and sustainable source of energy derived from organic matter and can be used to generate electricity and other forms of power. Common materials that can be used to develop biomass fuel include manure, forest debris, scrap lumber, mulch, sewage, certain crops and some kinds of waste residue. It does not include Atomic energy.
49. Tartaric Acid is not found in:
[A] Tamarind
[B] Grapes
[C] Unripe mangoes
[D] Spinach
[B] Grapes
[C] Unripe mangoes
[D] Spinach
Correct Answer: D [Spinach]
Notes:
Tartaric acid is a white crystalline organic acid. It occurs naturally in many plants, particularly grapes, unripe mangoes and tamarinds, and is one of the main acids found in wine. It is added to other foods to give a sour taste, and is used as an antioxidant. Oxalic acid is found in spinach.
Tartaric acid is a white crystalline organic acid. It occurs naturally in many plants, particularly grapes, unripe mangoes and tamarinds, and is one of the main acids found in wine. It is added to other foods to give a sour taste, and is used as an antioxidant. Oxalic acid is found in spinach.
50. A biochemical compound is any:
[A] mineral-based compound found in living things
[B] sulfur-based compound found in living things
[C] carbon-based compound found in living things
[D] hydrogen-based compound found in living things
[B] sulfur-based compound found in living things
[C] carbon-based compound found in living things
[D] hydrogen-based compound found in living things
Correct Answer: C [carbon-based compound found in living things]
Notes:
Biochemical compounds are made up of various elements and molecules. The most common elements found in biochemical compounds are carbon, hydrogen, oxygen, and nitrogen. These elements combine to form molecules such as carbohydrates, lipids, proteins, and nucleic acids. These molecules, in turn, can be further broken down into smaller units, such as amino acids and nucleotides. The specific components of a biochemical compound depend on the particular compound in question and its role in the organism.
Biochemical compounds are made up of various elements and molecules. The most common elements found in biochemical compounds are carbon, hydrogen, oxygen, and nitrogen. These elements combine to form molecules such as carbohydrates, lipids, proteins, and nucleic acids. These molecules, in turn, can be further broken down into smaller units, such as amino acids and nucleotides. The specific components of a biochemical compound depend on the particular compound in question and its role in the organism.