Chemistry GK MCQs for Competitive Exams for free online practice. Collection of Important previous year questions for preparation of upcoming SSC,RRB examinations.
Chemistry GK MCQs
Question 1: Which of the following dietary components provides the maximum energy per gram to humans?
A) Carbohydrates
B) Fats
C) Fibers
D) Proteins
Explanation: Fats are the primary source of energy in our diet. 1 gram of fat provides 9.5 kilocalories of energy, which is the highest among food components.
Question 2: Which of the following is a noble gas?
A) Ozone
B) Nitrogen
C) Hydrogen
D) Helium
Explanation: A noble gas is one that typically does not participate in chemical reactions and is always available in a free state.
Question 3: Which of the following elements belongs to the d-block of the modern periodic table?
A) Na
B) Fe
C) Ca
D) Mg
Explanation: From the electronic configurations of elements, it is evident that Fe belongs to the d-block because its outermost electron occupies the d-orbital.
Question 4: According to the modern periodic table, which element has the atomic number 30?
A) Co
B) Ni
C) Zn
D) Fe
Explanation: Zinc is a chemical element with the symbol Zn and atomic number 30.
Question 5: Which iron ore contains the highest amount of iron?
A) Magnetite
B) Hematite
C) Limonite
D) Siderite
Explanation: Magnetite contains the highest iron content, followed by other ores in the listed order.
Question 6: Who was awarded the Nobel Prize for the discovery of the neutron?
A) Chadwick
B) Rutherford
C) Niels Bohr
D) Roentgen
Explanation: Sir James Chadwick, a British physicist, was awarded the Nobel Prize in Physics in 1935 for his discovery of the neutron in 1932.
Question 7: What is the chemical name of Plaster of Paris?
A) Calcium hypochlorite
B) Calcium carbonate
C) Calcium oxide
D) Calcium sulfate hemihydrate
Explanation: Plaster of Paris is used for setting broken bones, making sculptures and toys, and producing chalk, among other uses.
Question 8: What is the chemical formula of washing soda?
A) Na2SO4
B) Ca(OH)2
C) Na2CO3 . 10H2O
D) NaHCO3
Explanation: Sodium carbonate is an inorganic compound with the chemical formula Na2CO3. It is commonly known as washing soda or soda ash and is used for laundry due to its alkaline nature.
Question 9: In a water molecule, what is the ratio of the masses of hydrogen and oxygen?
A) 1:4
B) 1:8
C) 1:16
D) 1:2
Explanation: The atomic mass of hydrogen is 1 u, and the atomic mass of oxygen is 16 u. Since a water molecule contains 2 hydrogen atoms and 1 oxygen atom, their mass ratio is 2:16 or 1:8.
Question 10: α particles are doubly charged ions of ____________.
A) Beryllium
B) Hydrogen
C) Helium
D) Lithium
Explanation: α particles consist of two protons and two neutrons. They are doubly charged helium ions.
Question 11: What is the atomic number of Copper?
A) 29
B) 26
C) 30
D) 32
Explanation: The atomic number of Copper is 29.
Question 12: What is the most common isotope of Oxygen?
A) O-16
B) O-17
C) O-18
D) O-19
Explanation: The most common isotope of Oxygen is O-16, which is found in nature in the highest abundance.
Question 13: What is the chemical name of NH₃ (Ammonia)?
A) Nitrogen Trihydride
B) Hydrogen Nitride
C) Nitrogen Hydride
D) Hydrogen Trinitride
Explanation: NH₃ is known as Nitrogen Hydride, commonly referred to as Ammonia.
Question 14: What is the chemical symbol for Mercury?
A) Hg
B) Pb
C) Au
D) Ag
Explanation: The chemical symbol for Mercury is Hg.
Question 15: Which acid is a harmful enzyme?
A) Hydrochloric Acid
B) Sulfuric Acid
C) Nitric Acid
D) Hydrofluoric Acid
Explanation: Hydrochloric Acid (HCl) is essential for digestion in the human stomach, but at high concentrations, it can be harmful.
Question 16: What is the approximate pH value of water?
A) 1
B) 7
C) 14
D) 9
Explanation: The pH value of water is around 7, making it neutral.
Question 17: Which element exhibits metallic properties?
A) Hydrogen
B) Oxygen
C) Calcium
D) Sulfur
Explanation: Calcium is a metal and shows properties similar to other metals.
Question 18: Which chemical is a strong acid?
A) Ethanol
B) Acetic Acid
C) Sulfuric Acid
D) Ammonia
Explanation: Sulfuric Acid (H₂SO₄) is a very strong acid.
Question 19: What is formed when carbon dioxide (CO₂) dissolves in water?
A) Carbonic Acid
B) Hydrochloric Acid
C) Sulfuric Acid
D) Nitric Acid
Explanation: When carbon dioxide dissolves in water, it forms carbonic acid (H₂CO₃).
Question 20: Which element has the highest relative atomic mass?
A) Hydrogen
B) Helium
C) Lithium
D) Uranium
Explanation: Uranium has the highest relative atomic mass.
Question 21: Which element remains in a gaseous state at room temperature?
A) Iron
B) Sodium
C) Nitrogen
D) Gold
Explanation: Nitrogen remains in a gaseous state at room temperature.
Question 22: Which metal is the lightest?
A) Lithium
B) Sodium
C) Potassium
D) Magnesium
Explanation: Lithium is the lightest metal.
Question 23: What is formed when hydrochloric acid and ammonia react?
A) Ammonium Chloride
B) Ammonium Hydroxide
C) Hydrogen Chloride
D) Hydrochloric Acid
Explanation: Hydrochloric acid and ammonia combine to form ammonium chloride (NH₄Cl).
Question 24: In chemistry, what does ‘pH’ stand for?
A) Measurement of acidity
B) Measurement of basicity
C) Measurement of gaseous state
D) Measurement of solid state
Explanation: pH measures acidity and basicity.
Question 25: Which acid is a natural acid found in fruits?
A) Sulfuric Acid
B) Acetic Acid
C) Citric Acid
D) Hydrochloric Acid
Explanation: Citric acid is found in fruits, especially lemons and oranges.
Question 26: Which element has only one electron in its outer shell?
A) Helium
B) Hydrogen
C) Lithium
D) Boron
Explanation: Hydrogen has only one electron in its outer shell.
Question 27: What is the atomic number of Iron (Fe)?
A) 20
B) 26
C) 29
D) 32
Explanation: The atomic number of Iron (Fe) is 26.
Question 28: What is the chemical symbol for Silver?
A) Ag
B) Au
C) Pb
D) Hg
Explanation: The chemical symbol for silver is Ag.
Question 29: Which element is commonly found as a diatomic molecule?
A) Hydrogen
B) Sodium
C) Calcium
D) Iron
Explanation: Hydrogen is commonly found as H₂.
Question 30: Which gas is produced during the oxidation and burning of water?
A) Oxygen
B) Hydrogen
C) Nitrogen
D) Carbon Dioxide
Explanation: Hydrogen gas is produced during the electrolysis of water.
Question 31: Which acid is predominant in acid rain?
A) Hydrochloric acid
B) Sulfuric acid
C) Citric acid
D) Acetic acid
Explanation: Sulfuric acid (H₂SO₄) plays a major role in acid rain.
Question 32: Which chemical is used as a pesticide?
A) Cysteine
B) Chloroform
C) DDT
D) Aniline
Explanation: DDT is used as a pesticide.
Question 33: Which is the most abundant element in the atmosphere?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Argon
Explanation: Nitrogen makes up 78% of the Earth’s atmosphere.
Question 34: Which element is most commonly used as a salt?
A) Sodium
B) Calcium
C) Potassium
D) Iron
Explanation: Sodium is the main element used in common salts like table salt (NaCl).
Question 35: What compound is formed by the combination of oxygen and hydrogen?
A) Methane
B) Ammonia
C) Water
D) Carbon dioxide
Explanation: Water (H₂O) is formed by the combination of oxygen and hydrogen.
Question 36: Which element is used in the production of atomic bombs?
A) Plutonium
B) Sodium
C) Boron
D) Magnesium
Explanation: Plutonium (Pu) is used in the production of atomic bombs.
Question 37: Which substance is used to clean teeth?
A) Calcium carbonate
B) Sodium chloride
C) Silica
D) Glycerine
Explanation: Silica is used in toothpaste for cleaning teeth.
Question 38: Which substance is called ‘white poison’ in the diet?
A) Salt
B) Sugar
C) Sodium bicarbonate
D) Calcium
Explanation: Sugar is often referred to as ‘white poison’ due to its excessive consumption leading to health issues.
Question 39: Which chemical is used to preserve food?
A) Acetic acid
B) Sulfur dioxide
C) Hydrochloric acid
D) Nitric acid
Explanation: Sulfur dioxide (SO₂) is used to preserve food.
Question 40: Which substance is a good conductor of electricity?
A) Wood
B) Plastic
C) Copper
D) Rubber
Explanation: Copper is an excellent conductor of electricity.
Question 41: Which compound is found in oily color?
A) Carbon dioxide
B) Potassium permanganate
C) Water
D) Sodium chloride
Explanation: Potassium permanganate (KMnO₄) has an oily color.
Question 42: What is the chemical symbol of Helium?
A) He
B) H
C) Hg
D) H₂
Explanation: The chemical symbol for Helium is He.
Question 43: Which chemical is used to extinguish fire?
A) Carbon dioxide
B) Hydrogen
C) Ammonia
D) Sulfur
Explanation: Carbon dioxide (CO₂) is used for extinguishing fires.
Question 44: Which element plays a significant role in DNA as an important biomolecule?
A) Carbon
B) Hydrogen
C) Nitrogen
D) Oxygen
Explanation: Nitrogen plays an essential role in the structure of DNA.
Question 45: Which element is used in radiotherapy?
A) Iodine
B) Sodium
C) Boron
D) Calcium
Explanation: Iodine is used in radiotherapy.
Question 46: Which chemical is used in burning and also found in fireworks?
A) Nitrogen
B) Potassium nitrate
C) Sodium chloride
D) Hydrochloric acid
Explanation: Potassium nitrate (KNO₃) is used in burning and in fireworks.
Question 47: Which color indicator is used to identify acidic properties?
A) Red
B) Blue
C) Green
D) Yellow
Explanation: Red color indicator is used to identify acidic properties.
Question 48: Which substance dissolves in water but not in oil?
A) Salt
B) Sugar
C) Flour
D) Fat
Explanation: Salt (sodium chloride) dissolves in water but not in oil.
Question 49: What is the most common example of a hydrogen bond?
A) Ammonia
B) Water
C) Carbon dioxide
D) Methane
Explanation: Water is the most common example of hydrogen bonding, where hydrogen of one water molecule bonds with the oxygen of another water molecule.
Question 50: Which element is used in batteries?
A) Lithium
B) Sodium
C) Calcium
D) Potassium
Explanation: Lithium is used in batteries.
Question 51: Which element is used in making steel?
A) Carbon
B) Silicon
C) Zinc
D) Platinum
Explanation: Carbon is used in making steel.
Question 52: Which element plays an important role in biological instruments?
A) Iron
B) Sodium
C) Calcium
D) Gold
Explanation: Calcium plays a vital role in biological structures such as bones and teeth.
Question 53: Which metal is used in galvanization to protect iron from corrosion and rust?
A) Chromium
B) Zinc
C) Rhodium
D) Tin
Explanation: Zinc is used in galvanization to protect iron from corrosion and rust.
Question 54: Bronze is an alloy of which of the following?
A) Copper and Zinc
B) Tin and Zinc
C) Copper and Tin
D) Iron and Zinc
Question 55: What is the bond called when electrons are shared between two elements?
A) Covalent bond
B) Hydrogen bond
C) Ionic bond
D) Dative bond
Explanation: A covalent bond is formed when electrons are shared between the atoms of the elements.
Question 56: The isotope of which element is used in cancer treatment?
A) Cobalt
B) Nickel
C) Aluminum
D) Iron
Explanation: Cobalt isotopes are used in cancer treatment.
Question 57: A naturally occurring organic compound with the formula (C6H5)2CO is?
A) Acetophenone
B) Benzophenone
C) Propiophenone
D) Methcathinone
Question 58: What is the atomic mass of sodium?
A) 13
B) 23
C) 40
D) 12
Explanation: The atomic number of sodium is 11, and it has 12 neutrons, making its atomic mass 11 + 12 = 23.
Question 59: Which gas is produced when lead nitrate is heated?
A) Nitrogen dioxide
B) Lead dioxide
C) Lead oxide
D) Nitrogen oxide
Explanation: When lead nitrate is heated, it decomposes to produce lead monoxide, nitrogen dioxide, and oxygen.
Question 60: Which chemical element from group 18 of the periodic table is produced in soil and rocks due to the natural radioactive decay of uranium?
A) Radon
B) Neon
C) Krypton
D) Oganesson