What is a chemical reaction?
a) A process that only involves physical changes
b) A process where the identity of a substance changes
c) A method to mix substances without change
d) A way to store chemical substances
Answer: b) A process where the identity of a substance changes

Which of the following indicates a chemical reaction has occurred?
a) Change in size
b) Change in color
c) Formation of bubbles
d) Both b) and c)
Answer: d) Both b) and c)

Why should a magnesium ribbon be cleaned before burning?
a) To remove the outer layer of magnesium oxide
b) To prevent it from burning
c) To add impurities to the ribbon
d) To ensure it stays shiny
Answer: a) To remove the outer layer of magnesium oxide

What is the purpose of balancing a chemical equation?
a) To make it visually appealing
b) To follow the law of conservation of mass
c) To change the reactants
d) To simplify chemical reactions
Answer: b) To follow the law of conservation of mass

What is formed when zinc reacts with dilute sulphuric acid?
a) Zinc oxide and water
b) Zinc sulphate and hydrogen gas
c) Zinc chloride and oxygen
d) Zinc hydroxide and nitrogen gas
Answer: b) Zinc sulphate and hydrogen gas

What is the word equation for the reaction of hydrogen with oxygen?
a) Hydrogen + Oxygen → Water
b) Hydrogen + Oxygen → Hydrogen peroxide
c) Hydrogen + Oxygen → Carbon dioxide
d) Hydrogen + Oxygen → Methane
Answer: a) Hydrogen + Oxygen → Water

Which gas is released when calcium carbonate is heated?
a) Oxygen
b) Hydrogen
c) Carbon dioxide
d) Nitrogen
Answer: c) Carbon dioxide

Which law is followed when balancing a chemical equation?
a) Law of Conservation of Momentum
b) Law of Conservation of Energy
c) Law of Conservation of Mass
d) Law of Conservation of Motion
Answer: c) Law of Conservation of Mass

What happens in a combination reaction?
a) Two or more substances combine to form a single product
b) A single compound breaks into simpler substances
c) Heat is absorbed from the surroundings
d) Two elements displace each other
Answer: a) Two or more substances combine to form a single product

What is the reaction called when energy is released in the form of heat?
a) Endothermic reaction
b) Exothermic reaction
c) Combination reaction
d) Neutralization reaction
Answer: b) Exothermic reaction

Which of the following is an example of an exothermic reaction?
a) Photosynthesis
b) Respiration
c) Decomposition of calcium carbonate
d) Melting of ice
Answer: b) Respiration

What is produced when sodium reacts with water?
a) Sodium hydroxide and hydrogen
b) Sodium chloride and hydrogen
c) Sodium oxide and water
d) Sodium carbonate and oxygen
Answer: a) Sodium hydroxide and hydrogen

Which reaction involves breaking a compound into simpler products?
a) Combination reaction
b) Displacement reaction
c) Decomposition reaction
d) Double displacement reaction
Answer: c) Decomposition reaction

What type of reaction is: 2AgCl → 2Ag + Cl₂?
a) Combination reaction
b) Displacement reaction
c) Decomposition reaction
d) Oxidation reaction
Answer: c) Decomposition reaction

What causes the color change when an iron nail is dipped in copper sulphate solution?
a) Oxidation of copper
b) Displacement of copper by iron
c) Formation of hydrogen gas
d) Reaction of copper with air
Answer: b) Displacement of copper by iron

What is the product of the reaction between barium chloride and sodium sulphate?
a) Sodium chloride and barium carbonate
b) Barium sulphate and sodium chloride
c) Sodium sulphate and barium chloride
d) Sodium carbonate and barium hydroxide
Answer: b) Barium sulphate and sodium chloride

What type of reaction involves exchange of ions between two reactants?
a) Combination reaction
b) Displacement reaction
c) Double displacement reaction
d) Redox reaction
Answer: c) Double displacement reaction

Which of the following is an example of a precipitation reaction?
a) NaCl + AgNO₃ → AgCl + NaNO₃
b) Zn + HCl → ZnCl₂ + H₂
c) H₂ + Cl₂ → 2HCl
d) CaCO₃ → CaO + CO₂
Answer: a) NaCl + AgNO₃ → AgCl + NaNO₃

In a redox reaction, what happens to the oxidized substance?
a) Gains oxygen
b) Loses oxygen
c) Gains hydrogen
d) Combines with water
Answer: a) Gains oxygen

Which reaction is an example of oxidation?
a) 2H₂ + O₂ → 2H₂O
b) CuO + H₂ → Cu + H₂O
c) Zn + CuSO₄ → ZnSO₄ + Cu
d) AgCl → Ag + Cl₂
Answer: a) 2H₂ + O₂ → 2H₂O

What is the brown substance formed on heating copper powder in air?
a) Copper carbonate
b) Copper hydroxide
c) Copper oxide
d) Copper nitrate
Answer: c) Copper oxide

In the reaction Zn + CuSO₄ → ZnSO₄ + Cu, which element is oxidized?
a) Zinc
b) Copper
c) Sulphur
d) Oxygen
Answer: a) Zinc

What is the substance reduced in the reaction CuO + H₂ → Cu + H₂O?
a) Copper
b) Copper oxide
c) Water
d) Hydrogen
Answer: b) Copper oxide

What is corrosion?
a) Reaction of a metal with water
b) Slow eating away of metals due to reactions with moisture and air
c) Melting of metals at high temperatures
d) Burning of metals in oxygen
Answer: b) Slow eating away of metals due to reactions with moisture and air

Why do chips manufacturers flush bags with nitrogen gas?
a) To kill bacteria
b) To prevent oxidation of oils
c) To maintain freshness
d) To increase the weight of the package
Answer: b) To prevent oxidation of oils

What is the term for a reaction in which energy is absorbed?
a) Exothermic reaction
b) Endothermic reaction
c) Displacement reaction
d) Combination reaction
Answer: b) Endothermic reaction

Which of the following reactions is an example of an endothermic process?
a) Burning of methane
b) Decomposition of calcium carbonate
c) Respiration
d) Neutralization of acid and base
Answer: b) Decomposition of calcium carbonate

What does the symbol (aq) indicate in a chemical equation?
a) Aqueous solution
b) Gaseous state
c) Solid state
d) Liquid state
Answer: a) Aqueous solution

What is the product formed when quicklime reacts with water?
a) Calcium carbonate
b) Calcium hydroxide
c) Calcium oxide
d) Calcium sulphate
Answer: b) Calcium hydroxide

What is the correct balanced chemical equation for the reaction of hydrogen and chlorine?
a) H₂ + Cl₂ → HCl
b) H₂ + Cl₂ → 2HCl
c) 2H₂ + Cl₂ → 2HCl
d) 2H₂ + 2Cl₂ → HCl
Answer: b) H₂ + Cl₂ → 2HCl

What is the process called when food becomes rancid?
a) Oxidation of fats and oils
b) Reduction of fats and oils
c) Fermentation of carbohydrates
d) Decomposition of proteins
Answer: a) Oxidation of fats and oils

What happens when silver chloride is exposed to sunlight?
a) It turns black
b) It turns grey
c) It forms silver bromide
d) It forms hydrogen chloride
Answer: b) It turns grey

What is the formula for glucose?
a) C₆H₁₂O₆
b) C₁₂H₂₂O₁₁
c) CH₄
d) CO₂
Answer: a) C₆H₁₂O₆

Which of these is a decomposition reaction?
a) 2H₂O → 2H₂ + O₂
b) H₂ + O₂ → H₂O
c) NaCl + AgNO₃ → AgCl + NaNO₃
d) CH₄ + 2O₂ → CO₂ + 2H₂O
Answer: a) 2H₂O → 2H₂ + O₂

In which reaction do two reactants form a single product?
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Redox reaction
Answer: a) Combination reaction

What type of reaction is: C + O₂ → CO₂?
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Double displacement reaction
Answer: a) Combination reaction

What is the balanced chemical equation for the reaction of magnesium with oxygen?
a) Mg + O → MgO
b) 2Mg + O₂ → 2MgO
c) Mg + O₂ → MgO
d) 2Mg + O → 2MgO
Answer: b) 2Mg + O₂ → 2MgO

What is the formula of lime water?
a) Ca(OH)₂
b) CaCO₃
c) CaO
d) CaCl₂
Answer: a) Ca(OH)₂

What is the insoluble product formed when sodium sulphate reacts with barium chloride?
a) Sodium chloride
b) Barium sulphate
c) Barium carbonate
d) Sodium hydroxide
Answer: b) Barium sulphate

Which gas is evolved during the reaction of zinc with hydrochloric acid?
a) Hydrogen
b) Oxygen
c) Nitrogen
d) Carbon dioxide
Answer: a) Hydrogen

Which of the following reactions is an example of a redox reaction?
a) Fe + CuSO₄ → FeSO₄ + Cu
b) 2H₂ + O₂ → 2H₂O
c) Both a and b
d) None of these
Answer: c) Both a and b

Which process prevents corrosion of metals?
a) Oxidation
b) Painting
c) Fermentation
d) Melting
Answer: b) Painting

What is the reaction between glucose and oxygen in the body called?
a) Digestion
b) Respiration
c) Fermentation
d) Photosynthesis
Answer: b) Respiration

What is the product of the decomposition of calcium carbonate?
a) Calcium hydroxide and carbon dioxide
b) Calcium oxide and water
c) Calcium oxide and carbon dioxide
d) Calcium chloride and water
Answer: c) Calcium oxide and carbon dioxide

What happens in a double displacement reaction?
a) Elements combine to form a product
b) Elements exchange places between compounds
c) A single compound breaks into simpler products
d) Heat is absorbed during the reaction
Answer: b) Elements exchange places between compounds

What is the reaction in which heat is absorbed?
a) Endothermic reaction
b) Exothermic reaction
c) Precipitation reaction
d) Displacement reaction
Answer: a) Endothermic reaction

Which gas turns lime water milky?
a) Hydrogen
b) Carbon dioxide
c) Oxygen
d) Nitrogen
Answer: b) Carbon dioxide

What is the chemical formula for marble?
a) Ca(OH)₂
b) CaCO₃
c) CaO
d) CaCl₂
Answer: b) CaCO₃

Which metal is more reactive: Zinc or Copper?
a) Zinc
b) Copper
c) Both are equally reactive
d) Neither is reactive
Answer: a) Zinc

What type of reaction is: NaOH + HCl → NaCl + H₂O?
a) Combination reaction
b) Displacement reaction
c) Neutralization reaction
d) Decomposition reaction
Answer: c) Neutralization reaction

What happens when silver nitrate is exposed to sunlight?
a) It decomposes to form silver and nitrogen dioxide
b) It decomposes to form silver and oxygen
c) It decomposes to form silver and chlorine
d) It decomposes to form silver bromide
Answer: c) It decomposes to form silver and chlorine

Which substance gives a characteristic blue color in solutions?
a) Zinc nitrate
b) Copper sulphate
c) Potassium chloride
d) Sodium sulphate
Answer: b) Copper sulphate

Which of the following reactions is a displacement reaction?
a) Zn + CuSO₄ → ZnSO₄ + Cu
b) HCl + NaOH → NaCl + H₂O
c) CaCO₃ → CaO + CO₂
d) H₂ + O₂ → H₂O
Answer: a) Zn + CuSO₄ → ZnSO₄ + Cu

What is the black coating on silver due to?
a) Oxidation
b) Corrosion
c) Reaction with sulphur compounds
d) Reaction with oxygen
Answer: c) Reaction with sulphur compounds

What is the gas evolved during the electrolysis of water?
a) Oxygen at the cathode and hydrogen at the anode
b) Hydrogen at the cathode and oxygen at the anode
c) Only oxygen is evolved
d) Only hydrogen is evolved
Answer: b) Hydrogen at the cathode and oxygen at the anode

What happens when ferrous sulphate crystals are heated?
a) They release oxygen
b) They decompose to form ferric oxide, sulphur dioxide, and sulphur trioxide
c) They combine with oxygen
d) They melt to form ferrous oxide
Answer: b) They decompose to form ferric oxide, sulphur dioxide, and sulphur trioxide

Which of the following is an example of a precipitation reaction?
a) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl
b) H₂ + O₂ → H₂O
c) Zn + CuSO₄ → ZnSO₄ + Cu
d) CaCO₃ → CaO + CO₂
Answer: a) BaCl₂ + Na₂SO₄ → BaSO₄ + 2NaCl

Which type of reaction takes place during photosynthesis?
a) Combination reaction
b) Endothermic reaction
c) Precipitation reaction
d) Displacement reaction
Answer: b) Endothermic reaction

What is formed when lead nitrate is heated?
a) Lead oxide, nitrogen dioxide, and oxygen
b) Lead chloride and water
c) Lead carbonate and oxygen
d) Lead hydroxide and carbon dioxide
Answer: a) Lead oxide, nitrogen dioxide, and oxygen

Which of the following represents oxidation?
a) Cu → CuO
b) CuO → Cu
c) ZnO → Zn
d) H₂O → H₂
Answer: a) Cu → CuO

What is the main cause of rancidity?
a) Reduction of fats and oils
b) Oxidation of fats and oils
c) Fermentation of carbohydrates
d) Reaction of fats with acids
Answer: b) Oxidation of fats and oils

What does the equation 2H₂ + O₂ → 2H₂O represent?
a) Combination reaction
b) Decomposition reaction
c) Neutralization reaction
d) Precipitation reaction
Answer: a) Combination reaction

Which of the following prevents rancidity?
a) Adding antioxidants
b) Storing food in airtight containers
c) Flushing with nitrogen gas
d) All of the above
Answer: d) All of the above

What is the balanced chemical equation for the decomposition of water?
a) H₂O → H₂ + O
b) 2H₂O → 2H₂ + O₂
c) H₂O → H₂ + O₂
d) 2H₂O → H₂ + O
Answer: b) 2H₂O → 2H₂ + O₂

What type of reaction occurs when calcium reacts with water?
a) Combination reaction
b) Displacement reaction
c) Decomposition reaction
d) Neutralization reaction
Answer: b) Displacement reaction

Which gas is produced during the reaction of sodium with water?
a) Oxygen
b) Nitrogen
c) Hydrogen
d) Chlorine
Answer: c) Hydrogen

What happens when iron is exposed to moisture and air?
a) It gets oxidized to form rust
b) It forms iron chloride
c) It forms ferrous oxide
d) It remains unchanged
Answer: a) It gets oxidized to form rust

What is the chemical formula for quicklime?
a) Ca(OH)₂
b) CaCO₃
c) CaO
d) CaSO₄
Answer: c) CaO

Which reaction is used in the manufacture of cement?
a) Decomposition of calcium carbonate
b) Combination of oxygen and hydrogen
c) Reaction of zinc with acid
d) Precipitation of calcium sulphate
Answer: a) Decomposition of calcium carbonate

What happens when ammonium chloride is mixed with water?
a) The solution becomes hot
b) The solution becomes cold
c) No temperature change
d) Ammonium gas is released
Answer: b) The solution becomes cold

In the reaction CuO + H₂ → Cu + H₂O, what is reduced?
a) Copper
b) Hydrogen
c) Copper oxide
d) Water
Answer: c) Copper oxide

What is the color of the precipitate formed when barium chloride reacts with sulphuric acid?
a) White
b) Yellow
c) Brown
d) Blue
Answer: a) White

Which of these reactions is exothermic?
a) Neutralization of acid and base
b) Dissolution of ammonium nitrate in water
c) Decomposition of calcium carbonate
d) Photosynthesis
Answer: a) Neutralization of acid and base

What is the main component of rust?
a) Fe₂O₃·xH₂O
b) FeO
c) Fe₂O₃
d) Fe(OH)₃
Answer: a) Fe₂O₃·xH₂O

What is formed when copper reacts with oxygen?
a) CuO
b) Cu₂O
c) Both CuO and Cu₂O
d) CuCl₂
Answer: c) Both CuO and Cu₂O

What is the product of the reaction between sodium hydroxide and hydrochloric acid?
a) Sodium chloride and water
b) Sodium oxide and water
c) Sodium carbonate and hydrogen
d) Sodium chloride and oxygen
Answer: a) Sodium chloride and water

What happens to magnesium when it burns in air?
a) It forms magnesium oxide
b) It forms magnesium chloride
c) It remains unchanged
d) It forms magnesium hydroxide
Answer: a) It forms magnesium oxide

What type of reaction is the rusting of iron?
a) Combination reaction
b) Redox reaction
c) Decomposition reaction
d) Precipitation reaction
Answer: b) Redox reaction

What gas is released when carbon reacts with oxygen?
a) Carbon monoxide
b) Carbon dioxide
c) Oxygen
d) Hydrogen
Answer: b) Carbon dioxide

What is the greenish layer formed on copper?
a) Copper sulphate
b) Copper oxide
c) Basic copper carbonate
d) Copper chloride
Answer: c) Basic copper carbonate

Which of the following is an example of a combination reaction?
a) 2H₂ + O₂ → 2H₂O
b) CaCO₃ → CaO + CO₂
c) Zn + HCl → ZnCl₂ + H₂
d) AgCl → Ag + Cl₂
Answer: a) 2H₂ + O₂ → 2H₂O

Why is nitrogen gas used in food packaging?
a) To add weight to the package
b) To prevent spoilage by reducing oxidation
c) To kill bacteria
d) To make the food crispier
Answer: b) To prevent spoilage by reducing oxidation

Which reaction involves the release of energy?
a) Respiration
b) Photosynthesis
c) Dissolution of ammonium chloride in water
d) Decomposition of calcium carbonate
Answer: a) Respiration

What is the main product when glucose reacts with oxygen during respiration?
a) Carbon dioxide and water
b) Methane and water
c) Carbon monoxide and oxygen
d) Oxygen and hydrogen
Answer: a) Carbon dioxide and water

What causes the color change in copper sulphate solution when an iron nail is dipped?
a) Formation of ferrous sulphate
b) Formation of ferric oxide
c) Formation of copper hydroxide
d) Formation of iron chloride
Answer: a) Formation of ferrous sulphate

What is the product formed when hydrogen reacts with chlorine?
a) Hydrochloric acid
b) Hydrogen chloride
c) Water
d) Chlorine oxide
Answer: b) Hydrogen chloride

What is the reaction called when carbon dioxide reacts with lime water?
a) Neutralization reaction
b) Precipitation reaction
c) Combination reaction
d) Displacement reaction
Answer: b) Precipitation reaction

What is the balanced chemical equation for the reaction between aluminium and copper chloride?
a) Al + CuCl → AlCl₃ + Cu
b) 2Al + 3CuCl₂ → 2AlCl₃ + 3Cu
c) Al + CuCl₂ → AlCl₃ + Cu
d) 2Al + CuCl → Al₂Cl₃ + Cu
Answer: b) 2Al + 3CuCl₂ → 2AlCl₃ + 3Cu

What happens to the temperature of the surroundings in an exothermic reaction?
a) It decreases
b) It increases
c) It remains unchanged
d) It fluctuates
Answer: b) It increases

What type of reaction is: 2AgCl → 2Ag + Cl₂?
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Neutralization reaction
Answer: b) Decomposition reaction

Why does copper sulphate solution lose its blue color in the reaction with zinc?
a) Zinc displaces copper from the solution
b) Zinc reacts with water
c) Zinc forms a precipitate
d) Zinc absorbs the color
Answer: a) Zinc displaces copper from the solution

What is the product of the reaction: ZnCO₃ → ZnO + CO₂?
a) Zinc oxide and water
b) Zinc carbonate and oxygen
c) Zinc oxide and carbon dioxide
d) Zinc hydroxide and carbon monoxide
Answer: c) Zinc oxide and carbon dioxide

What is the main characteristic of a double displacement reaction?
a) Exchange of ions between reactants
b) Release of energy
c) Formation of gas
d) Absorption of energy
Answer: a) Exchange of ions between reactants

What is the color of ferric oxide formed in a decomposition reaction?
a) Black
b) Brown
c) Green
d) White
Answer: b) Brown

Which type of reaction occurs in the electrolysis of water?
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Redox reaction
Answer: b) Decomposition reaction

What is the gas evolved when ammonium nitrate decomposes?
a) Hydrogen
b) Nitrogen
c) Oxygen
d) Carbon dioxide
Answer: b) Nitrogen

What is formed when carbon burns in limited oxygen?
a) Carbon monoxide
b) Carbon dioxide
c) Carbon tetrachloride
d) Methane
Answer: a) Carbon monoxide

What is an example of a neutralization reaction?
a) HCl + NaOH → NaCl + H₂O
b) Zn + HCl → ZnCl₂ + H₂
c) 2H₂ + O₂ → 2H₂O
d) AgNO₃ + NaCl → AgCl + NaNO₃
Answer: a) HCl + NaOH → NaCl + H₂O

What is the reaction called when two elements combine to form a compound?
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Neutralization reaction
Answer: a) Combination reaction

Which of the following is the best way to slow down oxidation in food?
a) Store food in airtight containers
b) Add antioxidants
c) Flush with nitrogen gas
d) All of the above
Answer: d) All of the above