1.What is the chemical formula for water?
- a) HO2
- b) H2O
- c) O2H
- d) H2Ho
Answer:b)H20
Explanation: Water is composed of two hydrogen atoms and one oxygen atom, hence the formula
2.Which gas is essential for human respiration?
- a) Nitrogen
- b) Oxygen
- c) Carbon dioxide
- d) Hydrogen
Answer:b) Oxygen
Explanation: Oxygen is required by humans to produce energy through cellular respiration.
3.What is the hardest natural substance found on Earth?
- a) Gold
- b) Iron
- c) Diamond
- d) Quartz
Answer: c) Diamond
Explanation: Diamond is the hardest natural substance due to the strong covalent bonding between its carbon atoms.
4.Which vitamin is produced in the human skin upon exposure to sunlight?
- a) Vitamin A
- b) Vitamin C
- c) Vitamin D
- d) Vitamin K
Answer: c) Vitamin D
Explanation: When exposed to UV rays from the sun, the skin synthesizes Vitamin D.
5.Which planet in our solar system is known as the 'Blue Planet'?
- a) Mars
- b) Earth
- c) Jupiter
- d) Neptune
Answer:b) Earth
Explanation:Earth is called the Blue Planet due to the abundant water covering its surface, making it appear blue from space.
6.What is the SI unit of force?
- a) Joule
- b) Pascal
- c) Newton
- d) Watt
Answer:c) Newton
Explanation:The SI unit of force is the Newton, named after Sir Isaac Newton, who formulated the laws of motion.
7.The boiling point of water at sea level is:
- a) 50°C
- b) 75°C
- c) 90°C
- d) 100°C
Answer:d) 100°C
Explanation: At sea level, the atmospheric pressure allows water to boil at 100°C.
8.Which of the following is a non-renewable resource?
- a) Solar energy
- b) Wind energy
- c) Coal
- d) Hydroelectric power
Answer:c) Coal
Explanation:Coal is a fossil fuel and non-renewable because it takes millions of years to form.
9.What is the primary function of red blood cells in the human body?
- a) Fighting infections
- b) Transporting oxygen
- c) Clotting blood
- d) Producing antibodies
Answer: b) Transporting oxygen
Explanation:Red blood cells contain hemoglobin, which binds to oxygen and transports it to various parts of the body.
10.What is the pH level of pure water?
- a) 5
- b) 7
- c) 9
- d) 12
Answer:b) 7
Explanation:Pure water is neutral and has a pH level of 7
11.Which of the following elements is essential for the formation of bones and teeth?
- a) Iron
- b) Calcium
- c) Potassium
- d) Sodium
Answer: b) Calcium
Explanation:Calcium is crucial for building and maintaining healthy bones and teeth.
12.Which process is used by plants to convert sunlight into food?
- a) Respiration
- b) Digestion
- c) Photosynthesis
- d) Transpiration
Answer:c) Photosynthesis
Explanation:Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen.
13.The smallest unit of an element is:
- a) Molecule
- b) Atom
- c) Electron
- d) Proton
Answer:b) Atom
Explanation: An atom is the smallest unit of an element, consisting of protons, neutrons, and electrons.
14.Which organ in the human body filters blood to remove waste and produce urine?
- a) Liver
- b) Kidney
- c) Heart
- d) Lungs
Answer:b) Kidney
Explanation:The kidneys filter blood to remove waste products and excess fluids, producing urine.
15.Which is the most abundant gas in the Earth's atmosphere?
- a) Oxygen
- b) Carbon dioxide
- c) Nitrogen
- d) Hydrogen
Answer:c) Nitrogen
Explanation:Nitrogen makes up about 78% of the Earth's atmosphere.
16.Which vitamin helps in clotting of blood?
- a) Vitamin A
- b) Vitamin B
- c) Vitamin D
- d) Vitamin K
Answer:d) Vitamin K
Explanation:Vitamin K is essential for synthesizing proteins that help in blood clotting.
17.Which is the nearest star to Earth?
- a) Sirius
- b) Alpha Centauri
- c) Proxima Centauri
- d) The Sun
Answer:d) The Sun
Explanation: The Sun is the closest star to Earth and provides the energy necessary for life on our planet.
18.What is the most common type of blood group among humans?
- a) AB+
- b) B+
- c) O+
- d) A+
Answer:c) O+
Explanation:O+ is the most common blood group in humans, followed by A+.
19.Which of the following is not a greenhouse gas?
- a) Carbon dioxide
- b) Methane
- c) Oxygen
- d) Nitrous oxide
Answer: c) Oxygen
Explanation:Oxygen is not a greenhouse gas. Greenhouse gases trap heat in the Earth's atmosphere, contributing to global warming.
20.Which part of the brain controls balance and coordination?
- a) Cerebrum
- b) Cerebellum
- c) Medulla
- d) Thalamus
Answer:b) Cerebellum
Explanation: The cerebellum controls motor movements, including balance, coordination, and posture.
21. What is the chemical symbol for Gold?
- a) Au
- b) Ag
- c) Fe
- d) Pb
Answer: a) Au
Explanation: The symbol Au is derived from the Latin name for gold,Aurum
22. Which gas do plants absorb from the atmosphere?
- a) Oxygen
- b) Carbon Dioxide
- c) Nitrogen
- d) Hydrogen
Answer: b) Carbon Dioxide
Explanation: Plants use carbon dioxide during photosynthesis to produce oxygen and glucose.
23. What is the powerhouse of the cell?
- a) Nucleus
- b) Mitochondria
- c) Chloroplast
- d) Endoplasmic Reticulum
Answer: b) Mitochondria
Explanation: Mitochondria generate energy in the form of ATP, thus termed the powerhouse.
24. What is the hardest natural substance on Earth?
- a) Gold
- b) Iron
- c) Diamond
- d) Quartz
Answer: c) Diamond
Explanation:Diamond, made entirely of carbon, is the hardest naturally occurring substance.
25. Which planet is known as the Red Planet?
- a) Mars
- b) Jupiter
- c) Venus
- d) Saturn
Answer: a) Mars
Explanation: Mars is called the Red Planet due to the presence of iron oxide (rust) on its surface.
26. What is the unit of electric current?
- a) Volt
- b) Ampere
- c) Watt
- d) Ohm
Answer: b) Ampere
Explanation:The ampere is the SI unit of electric current, named after André-Marie Ampère.
27. Which gas is most abundant in Earth's atmosphere?
- a) Oxygen
- b) Nitrogen
- c) Carbon Dioxide
- d) Argon
Answer: b) Nitrogen
Explanation: Nitrogen constitutes about 78% of the Earth's atmosphere.
28. What vitamin is produced when the skin is exposed to sunlight?
- a) Vitamin A
- b) Vitamin B
- c) Vitamin C
- d) Vitamin D
Answer: d) Vitamin D
Explanation: Sunlight helps the skin produce Vitamin D, which is essential for bone health.
29. Who discovered penicillin?
- a) Marie Curie
- b) Alexander Fleming
- c) Isaac Newton
- d) Albert Einstein
Answer: b) Alexander Fleming
Explanation:Fleming discovered penicillin in 1928, which later became the first antibiotic.
30. Which part of the plant conducts photosynthesis?
- a) Root
- b) Leaf
- c) Stem
- d) Flower
Answer: b) Leaf
Explanation:Leaves contain chlorophyll, which is necessary for photosynthesis.
31. What is the chemical formula for table salt?
- a) NaCl
- b) H2SO4
- c) KCl
- d) CaCO3
Answer: a) NaCl
Explanation: Table salt is made of sodium (Na) and chloride (Cl), forming NaCl.
32. Which is the largest planet in our solar system?
- a) Earth
- b) Jupiter
- c) Saturn
- d) Neptune
Answer: b) Jupiter
Explanation: Jupiter is the largest planet in the solar system, with a mass over 300 times that of Earth.
33. What is the boiling point of water at sea level?
- a) 50°C
- b) 75°C
- c) 100°C
- d) 150°C
Answer: c) 100°C
Explanation: Water boils at 100°C (212°F) at sea level.
34. Which of the following is not a state of matter?
- a) Solid
- b) Liquid
- c) Gas
- d) Plasma
Answer: d) Plasma
Explanation:Plasma is a state of matter, but not as common as solid, liquid, or gas.
35. Which organ in the human body filters blood?
- a) Heart
- b) Liver
- c) Kidney
- d) Lung
Answer: c) Kidney
Explanation: The kidneys filter waste from the blood and produce urine.
36. What is the study of fungi called?
- a) Botany
- b) Mycology
- c) Zoology
- d) Ecology
Answer: b) Mycology
Explanation:Mycology is the branch of biology concerned with the study of fungi.
37. Which planet is closest to the Sun?
- a) Earth
- b) Venus
- c) Mercury
- d) Mars
Answer: c) Mercury
Explanation:Mercury is the closest planet to the Sun.
38. How many chromosomes do humans have?
- a) 23
- b) 24
- c) 46
- d) 48
Answer: c) 46
Explanation:Humans have 46 chromosomes, arranged in 23 pairs.
39. What does DNA stand for?
- a) Deoxyribonucleic Acid
- b) Deoxyribosome Acid
- c) Dioxyribonucleic Acid
- d) Double Nucleic Acid
Answer: a) Deoxyribonucleic Acid
Explanation:DNA stands for Deoxyribonucleic Acid, which contains genetic information.
40. Which gas is essential for respiration?
- a) Nitrogen
- b) Carbon Dioxide
- c) Oxygen
- d) Helium
Answer: c) Oxygen
Explanation:Oxygen is essential for respiration in most living organisms.
41. What is the SI unit of force?
- a) Joule
- b) Newton
- c) Watt
- d) Pascal
Answer: b) Newton
Explanation:The SI unit of force is the Newton, named after Sir Isaac Newton.
42. Which planet has the most moons?
- a) Earth
- b) Mars
- c) Saturn
- d) Jupiter
Answer: d) Jupiter
Explanation:Jupiter has 79 known moons, the highest of any planet.
24. What is the primary gas found in the sun?
- a) Oxygen
- b) Helium
- c) Hydrogen
- d) Carbon
Answer: c) Hydrogen
Explanation: Hydrogen makes up about 75% of the Sun's mass.
25. Which element is necessary for the formation of hemoglobin in blood?
- a) Calcium
- b) Potassium
- c) Iron
- d) Zinc
Answer: c) Iron
Explanation: Iron is essential for hemoglobin to carry oxygen in red blood cells.
26. Which is the smallest particle of an element?
- a) Molecule
- b) Atom
- c) Proton
- d) Neutron
Answer: b) Atom
Explanation:An atom is the smallest unit of an element that retains the properties of that element.
27. What is the most abundant element in the universe?
- a) Oxygen
- b) Hydrogen
- c) Carbon
- d) Helium
Answer: b) Hydrogen
Explanation:Hydrogen makes up approximately 75% of the universe's elemental mass.
28. How many bones are in the adult human body?
- a) 206
- b) 205
- c) 210
- d) 208
Answer: a) 206
Explanation:The adult human body consists of 206 bones.
29. Which vitamin helps in clotting of blood?
- a) Vitamin A
- b) Vitamin K
- c) Vitamin C
- d) Vitamin D
Answer: b) Vitamin K
Explanation: Vitamin K is essential for the blood clotting process.
30. Which gas is used in the process of photosynthesis?
- a) Oxygen
- b) Carbon Dioxide
- c) Nitrogen
- d) Helium
31.Which gas is most abundant in the Earth's atmosphere?
- a) Oxygen
- b) Carbon dioxide
- c) Nitrogen
- d) Argon
Answer c) Nitrogen
Explanation: Nitrogen makes up about 78% of the Earth's atmosphere.
32.Which acid is commonly found in vinegar?
- a) Hydrochloric acid
- b) Sulfuric acid
- c) Acetic acid
- d) Citric acid
Answer:c) Acetic acid
Explanation: Vinegar contains acetic acid, typically about 5-8%.
33.Which of the following is a noble gas?
- a) Chlorine
- b) Neon
- c) Fluorine
- d) Phosphorus
Answer: b) Neon
Explanation: Neon is a noble gas found in Group 18 of the periodic table.
34.Which element is present in all organic compounds?
- a) Oxygen
- b) Carbon
- c) Hydrogen
- d) Nitrogen
Answer: b) Carbon
Explanation: Carbon is the essential element in all organic compounds.
35.Which compound is used in the manufacture of soaps and detergents?
- a) Sodium hydroxide
- b) Sodium chloride
- c) Potassium nitrate
- d) Calcium carbonate
Answer: a) Sodium hydroxide
Explanation: Sodium hydroxide (NaOH) is used in saponification to make soap.
36.Which gas is produced by the combustion of fossil fuels and contributes to global warming?
- a) Oxygen
- b) Nitrogen
- c) Carbon dioxide
- d) Hydrogen
Answer: c) Carbon dioxide
Explanation: Carbon dioxide is a greenhouse gas produced during fossil fuel combustion.
37.What is the chemical formula for table salt?
- a) NaCl
- b) KCl
- c) NaOH
- d) HCl
Answer: a) NaCl
Explanation: Table salt is composed of sodium (Na) and chloride (Cl) ions.
38.Which of the following is an allotrope of carbon?
- a) Diamond
- b) Water
- c) Sulfur
- d) Ammonia
Answer: a) Diamond
Explanation: Diamond is one of the allotropes of carbon, along with graphite and graphene.
39.Which element is the primary component of the Sun?
- a) Helium
- b) Oxygen
- c) Nitrogen
- d) Hydrogen
Answer: d) Hydrogen
Explanation: Hydrogen accounts for around 75% of the Sun's mass.
40.Which gas is responsible for the characteristic odor of rotten eggs?
- a) Methane
- b) Hydrogen sulfide
- c) Carbon monoxide
- d) Ammonia
Answer: b) Hydrogen sulfide
Explanation: Hydrogen sulfide (H₂S) gives off a smell similar to that of rotten eggs.
41.Which process is used to separate a mixture of liquids with different boiling points?
- a) Filtration
- b) Distillation
- c) Sublimation
- d) Evaporation
Answer: b) Distillation
Explanation: Distillation separates liquids based on their boiling points.
42.Which chemical is commonly used to disinfect drinking water?
- a) Chlorine
- b) Hydrogen peroxide
- c) Sodium chloride
- d) Methanol
Answer: a) Chlorine
Explanation: Chlorine is used to disinfect water and kill bacteria.
43.Which of the following is a chemical change?
- a) Melting of ice
- b) Evaporation of water
- c) Rusting of iron
- d) Breaking of glass
Answer: c) Rusting of iron
Explanation: Rusting involves a chemical reaction between iron and oxygen.
44.Which element is a liquid at room temperature?
- a) Bromine
- b) Carbon
- c) Sodium
- d) Sulfur
Answer: a) Bromine
Explanation: Bromine is one of the few elements that exist as a liquid at room temperature.
45.Which is the most electronegative element in the periodic table?
- a) Fluorine
- b) Oxygen
- c) Chlorine
- d) Nitrogen
Answer: a) Fluorine
Explanation: Fluorine is the most electronegative element, meaning it has a high tendency to attract electrons.
46.What is the common name for sodium bicarbonate?
- a) Table salt
- b) Baking soda
- c) Vinegar
- d) Bleach
Answer: b) Baking soda
Explanation: Sodium bicarbonate (NaHCO₃) is commonly known as baking soda.
47. Which of the following is a molecular formula of glucose?
- a) C₂H₆O₂
- b) C₆H₁₂O₆
- c) C₃H₈O₃
- d) C₇H₁₄O₂
Answer: b) C₆H₁₂O₆
Explanation: Glucose has the chemical formula C₆H₁₂O₆.
48.Which element is known as the 'King of Chemicals'?
- a) Oxygen
- b) Hydrogen
- c) Sulfur
- d) Nitrogen
Answer: c) Sulfur
Explanation: Sulfur is referred to as the 'King of Chemicals' due to its wide range of industrial uses.
49.Which metal is most commonly used in electrical wiring?
- a) Iron
- b) Copper
- c) Aluminum
- d) Silver
Answer: b) Copper
Explanation: Copper is an excellent conductor of electricity and is used extensively in electrical wiring.
50.Which element is the lightest of all elements?
- a) Helium
- b) Oxygen
- c) Hydrogen
- d) Lithium
Answer: c) Hydrogen
Explanation: Hydrogen is the lightest and most abundant element in the universe.
51.Which element is used in the filament of electric bulbs?
a) Copper
b) Tungsten
c) Iron
d) Aluminum
Answer: b) Tungsten
Explanation: Tungsten has a high melting point and is used as the filament in light bulbs.
Understood! Here’s the continuation from question 51:
51. Which element is used in the filament of electric bulbs?
a) Copper
b) Tungsten
c) Iron
d) Aluminum
Answer: b) Tungsten
Explanation: Tungsten has a high melting point and is used as the filament in light bulbs.
52. What is the common name for calcium carbonate?
a) Chalk
b) Sugar
c) Salt
d) Baking powder
Answer: a) Chalk
Explanation: Calcium carbonate is found in chalk, limestone, and marble.
53. Which gas is commonly known as "laughing gas"?
a) Nitrous oxide
b) Carbon dioxide
c) Sulfur dioxide
d) Oxygen
Answer: a) Nitrous oxide
Explanation: Nitrous oxide (N₂O) is commonly referred to as laughing gas due to its anesthetic effects.
54. Which metal is used to galvanize iron?
a) Zinc
b) Copper
c) Silver
d) Aluminum
Answer: a) Zinc
Explanation: Galvanization is the process of coating iron with zinc to prevent rusting.
55. Which acid is present in lemons?
a) Hydrochloric acid
b) Citric acid
c) Sulfuric acid
d) Acetic acid
Answer: b) Citric acid
Explanation: Lemons contain citric acid, giving them their sour taste.
56. Which chemical is used to preserve biological specimens?
a) Formaldehyde
b) Ethanol
c) Acetone
d) Glycerin
Answer: a) Formaldehyde
Explanation: Formaldehyde is used as a preservative for biological specimens.
57. Which gas is used in the production of ammonia?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Methane
Answer: b) Nitrogen
Explanation: Ammonia is produced through the Haber process using nitrogen and hydrogen.
58. What is the pH of pure water at room temperature?
a) 7
b) 5
c) 9
d) 2
Answer: a) 7
Explanation: Pure water has a neutral pH of 7 at room temperature.
59. What is the chemical symbol for gold?
a) Ag
b) Au
c) Al
d) Ga
Answer: b) Au
Explanation: The chemical symbol for gold is Au, derived from its Latin name "Aurum."
60. Which gas is known as a "noble gas"?
a) Nitrogen
b) Argon
c) Oxygen
d) Carbon dioxide
Answer: b) Argon
Explanation: Argon is a noble gas, which is chemically inert and belongs to Group 18 of the periodic table.
61. Which element is necessary for the formation of hemoglobin in the blood?
a) Calcium
b) Iron
c) Sodium
d) Potassium
Answer: b) Iron
Explanation: Iron is an essential component of hemoglobin, which carries oxygen in the blood.
62. What is the primary chemical component of sand?
a) Calcium oxide
b) Silicon dioxide
c) Sodium chloride
d) Aluminum oxide
Answer: b) Silicon dioxide
Explanation: Sand is primarily made of silicon dioxide (SiO₂), also known as silica.
63. Which chemical element is the main component of diamonds?
a) Carbon
b) Nitrogen
c) Oxygen
d) Sulfur
Answer: a) Carbon
Explanation: Diamonds are made entirely of carbon atoms arranged in a crystal structure.
64. Which gas is responsible for the depletion of the ozone layer?
a) Carbon monoxide
b) Nitrous oxide
c) Chlorofluorocarbons (CFCs)
d) Methane
Answer: c) Chlorofluorocarbons (CFCs)
Explanation: CFCs break down ozone molecules, leading to the depletion of the ozone layer.
65. What is the chemical formula for ammonia?
a) NH₄
b) NH₃
c) NO₂
d) N₂O
Answer: b) NH₃
Explanation: The chemical formula for ammonia is NH₃, consisting of one nitrogen atom and three hydrogen atoms.
66. What is the process of converting a solid directly into a gas called?
a) Condensation
b) Sublimation
c) Evaporation
d) Melting
Answer: b) Sublimation
Explanation: Sublimation is the process by which a solid changes directly into a gas without passing through the liquid state.
67. Which acid is commonly found in soft drinks?
a) Sulfuric acid
b) Phosphoric acid
c) Hydrochloric acid
d) Nitric acid
Answer: b) Phosphoric acid
Explanation: Phosphoric acid is commonly used in soft drinks to add a tangy flavor and to act as a preservative.
68. Which chemical element is known as "quick silver"?
a) Silver
b) Mercury
c) Lead
d) Tin
Answer: b) Mercury
Explanation: Mercury is also known as quicksilver because of its silvery liquid appearance.
69. What is the atomic number of oxygen?
a) 6
b) 7
c) 8
d) 9
Answer: c) 8
Explanation: Oxygen has an atomic number of 8, meaning it has 8 protons in its nucleus.
70. Which compound is the main constituent of natural gas?
a) Ethane
b) Propane
c) Butane
d) Methane
Answer: d) Methane
Explanation: Methane (CH₄) is the primary component of natural gas.
71. Which element is used in making lead-acid batteries?
a) Iron
b) Lead
c) Zinc
d) Aluminum
Answer: b) Lead
Explanation: Lead is used in lead-acid batteries, which are commonly used in vehicles.
72. Which acid is known as the "king of chemicals"?
a) Hydrochloric acid
b) Nitric acid
c) Sulfuric acid
d) Acetic acid
Answer: c) Sulfuric acid
Explanation: Sulfuric acid is called the "king of chemicals" due to its wide range of industrial applications.
73. Which element is commonly used in fireworks to produce a bright red color?
a) Copper
b) Potassium
c) Strontium
d) Magnesium
Answer: c) Strontium
Explanation: Strontium salts are used in fireworks to produce a bright red flame.
74. What is the main gas found in LPG (Liquefied Petroleum Gas)?
a) Butane
b) Methane
c) Ethane
d) Propane
Answer: a) Butane
Explanation: LPG primarily consists of butane and propane gases.
75. What is the chemical formula for sulfuric acid?
a) HNO₃
b) H₂SO₄
c) HCl
d) CH₃COOH
Answer: b) H₂SO₄
Explanation: The chemical formula for sulfuric acid is H₂SO₄, consisting of hydrogen, sulfur, and oxygen atoms.
76. Which element is used in making matches and fireworks?
a) Phosphorus
b) Sodium
c) Calcium
d) Potassium
Answer: a) Phosphorus
Explanation: Phosphorus is used in match heads and fireworks due to its ability to ignite easily.
77. Which gas turns limewater milky?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Hydrogen
Answer: b) Carbon dioxide
Explanation: Carbon dioxide reacts with calcium hydroxide in limewater to form calcium carbonate, which turns the solution milky.
78. What is the chemical name of rust?
a) Iron oxide
b) Copper sulfate
c) Sodium chloride
d) Magnesium oxide
Answer: a) Iron oxide
Explanation: Rust is primarily composed of iron oxide, formed when iron reacts with oxygen and moisture.
79. Which element is known as the "metal of the future" due to its lightweight and strong properties?
a) Iron
b) Titanium
c) Aluminum
d) Copper
Answer: b) Titanium
Explanation: Titanium is known for its high strength-to-weight ratio and resistance to corrosion, making it a valuable material for future technologies.
80. Which gas is used in fire extinguishers to put out flames?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Helium
Answer: b) Carbon dioxide
Explanation: Carbon dioxide is used in fire extinguishers as it displaces oxygen and cools the fire.
81. What is the common name of sodium chloride?
a) Sugar
b) Salt
c) Baking powder
d) Chalk
Answer: b) Salt
Explanation: Sodium chloride (NaCl) is commonly known as table salt.
82. Which substance is used as a coolant in car radiators?
a) Water
b) Ethylene glycol
c) Methanol
d) Acetone
Answer: b) Ethylene glycol
Explanation: Ethylene glycol is used in car radiators as a coolant due to its high boiling point and low freezing point.
83. What is the chemical symbol for silver?
a) Ag
b) Au
c) Pb
d) Si
Answer: a) Ag
Explanation: The chemical symbol for silver is Ag, derived from the Latin word "Argentum."
84. Which metal is extracted from bauxite ore?
a) Iron
b) Copper
c) Aluminum
d) Zinc
Answer: c) Aluminum
Explanation: Bauxite is the primary ore from which aluminum is extracted.
85. Which chemical is used as a bleaching agent in the textile industry?
a) Hydrogen peroxide
b) Sodium chloride
c) Calcium carbonate
d) Ammonium nitrate
Answer: a) Hydrogen peroxide
Explanation: Hydrogen peroxide is used as a bleaching agent due to its strong oxidizing properties.
86. Which element is essential for the production of nuclear energy?
a) Iron
b) Uranium
c) Sodium
d) Lead
Answer: b) Uranium
Explanation: Uranium is used as fuel in nuclear reactors due to its ability to undergo fission.
87. Which gas is used in neon signs?
a) Helium
b) Argon
c) Neon
d) Xenon
Answer: c) Neon
Explanation: Neon gas is used in neon signs, producing a bright glow when electricity passes through it.
88. Which acid is known as "oil of vitriol"?
a) Nitric acid
b) Acetic acid
c) Hydrochloric acid
d) Sulfuric acid
Answer: d) Sulfuric acid
Explanation: Sulfuric acid is historically referred to as "oil of vitriol" due to its oily appearance.
89. What is the main component of paper?
a) Protein
b) Cellulose
c) Starch
d) Keratin
Answer: b) Cellulose
Explanation: Paper is primarily composed of cellulose fibers derived from wood pulp.
90. Which metal is commonly used in the manufacturing of coins?
a) Copper
b) Tin
c) Zinc
d) Silver
Answer: a) Copper
Explanation: Copper and its alloys, such as bronze and brass, are commonly used in coin manufacturing.
91. Which gas is essential for respiration in humans?
a) Carbon dioxide
b) Nitrogen
c) Oxygen
d) Hydrogen
Answer: c) Oxygen
Explanation: Oxygen is essential for respiration, allowing humans to produce energy from food.
92. Which element is used as a catalyst in the hydrogenation of oils?
a) Platinum
b) Gold
c) Lead
d) Iron
Answer: a) Platinum
Explanation: Platinum and other noble metals are used as catalysts in the hydrogenation of oils.
93. Which metal is the best conductor of electricity?
a) Copper
b) Silver
c) Gold
d) Aluminum
Answer: b) Silver
Explanation: Silver has the highest electrical conductivity of all metals.
94. What is the chemical formula for baking soda?
a) NaOH
b) Na₂CO₃
c) NaHCO₃
d) K₂CO₃
Answer: c) NaHCO₃
Explanation: Baking soda is sodium bicarbonate, with the chemical formula NaHCO₃.
95. Which gas is produced during photosynthesis?
a) Carbon dioxide
b) Oxygen
c) Methane
d) Nitrogen
Answer: b) Oxygen
Explanation: During photosynthesis, plants produce oxygen as a byproduct.
96. Which metal is protected by a thin layer of oxide on its surface to prevent corrosion?
a) Iron
b) Aluminum
c) Copper
d) Zinc
Answer: b) Aluminum
Explanation: Aluminum forms a protective oxide layer that prevents further corrosion.
97. Which acid is commonly used in car batteries?
a) Hydrochloric acid
b) Nitric acid
c) Sulfuric acid
d) Acetic acid
Answer: c) Sulfuric acid
Explanation: Sulfuric acid is used in car batteries as the electrolyte.
98. What is the chemical symbol for potassium?
a) K
b) P
c) Ca
d) Pt
Answer: a) K
Explanation: The chemical symbol for potassium is K, derived from its Latin name "Kalium."
99. Which compound is responsible for the blue color of the sky?
a) Carbon dioxide
b) Water vapor
c) Nitrogen
d) Rayleigh scattering
Answer: d) Rayleigh scattering
Explanation: Rayleigh scattering of sunlight by atmospheric particles causes the blue color of the sky.
100. Which element is known as the "building block of life"?
a) Hydrogen
b) Oxygen
c) Carbon
d) Nitrogen
Answer: c) Carbon
Explanation: Carbon is considered the building block of life due to its ability to form complex molecules essential for living organisms.
