What happens when milk is left at room temperature during summers?
- A) It evaporates.
- B) It curdles.
- C) It freezes.
- D) It remains unchanged.
- Answer: B) It curdles.
What happens to an iron tawa/pan/nail when left exposed to humid atmosphere?
- A) It rusts.
- B) It melts.
- C) It breaks.
- D) It remains unchanged.
- Answer: A) It rusts.
What happens when grapes get fermented?
- A) They dry up.
- B) They produce alcohol.
- C) They remain fresh.
- D) They turn into water.
- Answer: B) They produce alcohol.
What happens when food is cooked?
- A) It burns.
- B) It undergoes a chemical change.
- C) It freezes.
- D) It remains the same.
- Answer: B) It undergoes a chemical change.
What happens when food gets digested in our body?
- A) It evaporates.
- B) It is converted into simpler substances.
- C) It freezes.
- D) It remains unchanged.
- Answer: B) It is converted into simpler substances.
What happens when we respire?
- A) Oxygen is converted to carbon dioxide.
- B) Carbon dioxide is converted to oxygen.
- C) Water is produced.
- D) Food is digested.
- Answer: A) Oxygen is converted to carbon dioxide.
What observation indicates a chemical reaction has taken place?
- A) Change in state.
- B) Change in color.
- C) Evolution of a gas.
- D) All of the above.
- Answer: D) All of the above.
Which reaction is an example of a combination reaction?
- A) Zn + H2SO4 → ZnSO4 + H2
- B) CaO + H2O → Ca(OH)2
- C) 2AgCl → 2Ag + Cl2
- D) 2H2O → 2H2 + O2
- Answer: B) CaO + H2O → Ca(OH)2
What type of reaction occurs when magnesium burns in air?
- A) Decomposition reaction.
- B) Combination reaction.
- C) Displacement reaction.
- D) Double displacement reaction.
- Answer: B) Combination reaction.
What is the product of burning magnesium in air?
- A) Magnesium carbonate.
- B) Magnesium oxide.
- C) Magnesium chloride.
- D) Magnesium hydroxide.
- Answer: B) Magnesium oxide.
What do the substances on the left-hand side of a chemical equation represent?
- A) Products.
- B) Reactants.
- C) Catalysts.
- D) Coefficients.
- Answer: B) Reactants.
In the reaction Zn + H2SO4 → ZnSO4 + H2, what is ZnSO4?
- A) Reactant.
- B) Product.
- C) Catalyst.
- D) Coefficient.
- Answer: B) Product.
What law states that mass can neither be created nor destroyed in a chemical reaction?
- A) Law of Definite Proportions.
- B) Law of Multiple Proportions.
- C) Law of Conservation of Mass.
- D) Law of Gases.
- Answer: C) Law of Conservation of Mass.
In the equation Fe + H2O → Fe3O4 + H2, which element do you balance last?
- A) Iron.
- B) Oxygen.
- C) Hydrogen.
- D) All are balanced simultaneously.
- Answer: A) Iron.
In the balanced equation 3Fe + 4H2O → Fe3O4 + 4H2, how many molecules of water are there?
- A) 1.
- B) 2.
- C) 3.
- D) 4.
- Answer: D) 4.
What is the state symbol for a substance in a solution in water?
- A) (s).
- B) (l).
- C) (g).
- D) (aq).
- Answer: D) (aq).
In the reaction CO + 2H2 → CH3OH, what does the arrow indicate?
- A) Reactants.
- B) Products.
- C) Direction of the reaction.
- D) Temperature.
- Answer: C) Direction of the reaction.
Which process is an example of an exothermic reaction?
- A) Melting of ice.
- B) Boiling of water.
- C) Respiration.
- D) Electrolysis of water.
- Answer: C) Respiration.
What type of reaction is CaCO3 → CaO + CO2?
- A) Combination reaction.
- B) Decomposition reaction.
- C) Displacement reaction.
- D) Double displacement reaction.
- Answer: B) Decomposition reaction.
Which reaction is used in black and white photography?
- A) 2AgCl → 2Ag + Cl2.
- B) 2H2O → 2H2 + O2.
- C) CaCO3 → CaO + CO2.
- D) Zn + H2SO4 → ZnSO4 + H2.
- Answer: A) 2AgCl → 2Ag + Cl2.
In the reaction Fe + CuSO4 → FeSO4 + Cu, what type of reaction is this?
- A) Combination reaction.
- B) Decomposition reaction.
- C) Displacement reaction.
- D) Double displacement reaction.
- Answer: C) Displacement reaction.
What color change is observed when silver chloride is exposed to sunlight?
- A) White to black.
- B) White to gray.
- C) Black to white.
- D) Gray to white.
- Answer: B) White to gray.
What is the main product when lead nitrate is heated?
- A) Lead chloride.
- B) Lead oxide.
- C) Lead sulphate.
- D) Lead carbonate.
- Answer: B) Lead oxide.
What type of reaction occurs when an electric current passes through water?
- A) Combination reaction.
- B) Decomposition reaction.
- C) Displacement reaction.
- D) Double displacement reaction.
- Answer: B) Decomposition reaction.
What is the by-product when calcium hydroxide reacts with carbon dioxide?
- A) Calcium carbonate.
- B) Calcium oxide.
- C) Calcium chloride.
- D) Calcium sulphate.
- Answer: A) Calcium carbonate.
What form of energy is used in the decomposition of water into hydrogen and oxygen?
- A) Heat.
- B) Light.
- C) Electricity.
- D) Sound.
- Answer: C) Electricity.
What happens to the temperature of a beaker when calcium oxide reacts with water?
- A) It decreases.
- B) It increases.
- C) It remains constant.
- D) It fluctuates.
- Answer: B) It increases.
What gas is released when zinc reacts with hydrochloric acid?
- A) Oxygen.
- B) Nitrogen.
- C) Hydrogen.
- D) Carbon dioxide.
- Answer: C) Hydrogen.
What is observed when copper sulphate solution reacts with iron?
- A) Solution turns green.
- B) Solution turns blue.
- C) Solution remains colorless.
- D) Solution turns brown.
- Answer: A) Solution turns green.
What is the main observation in a displacement reaction?
- A) Change in color.
- B) Formation of precipitate.
- C) Evolution of gas.
- D) One element displaces another.
- Answer: D) One element displaces another
Other Related Questions For Practicing Before the Exam
- MCQ Test for Chemical Reactions and Equations Class 10
- Support MCQs Answer: Chemical Reactions and Equations Class 10
- Give an example of a double displacement reaction
- Name reducing agent in the given chemical reaction: 3MnO2 + 4Al → 3Mn + 2Al2O3
- Name the brown coloured gas evolved when lead nitrate crystals are heated in a dry test-tube
- Give reasons: Silver chloride is stored in dark-colored bottles.
- What changes do you observe in iron nails and the color of the copper sulphate solution if iron nails are dipped in CuSO₄ solution for some time?
- Identify the chemical change: Melting of ice or conversion of milk into curd.
- Why is respiration considered an exothermic reaction?
- Why do copper vessels lose shine when exposed to air?
- Potato chips manufacturers fill the packet of chips with nitrogen gas. Why?
- Why do we store silver chloride in dark coloured bottles in labs?
- Write chemical equations of a double displacement reaction
- N₂ + 3H₂ → 2NH₃, name the type of reaction.
- What happens when milk is left open at room temperature during summer?
- What happens when quicklime is added to water?
- Define combination reaction. Give two examples of combination reactions which are exothermic in nature.
- What is decomposition reaction? Explain with the help of an example.
- Name and state the law which is kept in mind when we balance a chemical equation
- Give one example of each: (a) Chemical reaction showing evolution of gas:
- What is rancidity? Write two ways by which it can be prevented.
- What are two conditions which promote corrosion?
- A small amount of Ferrous sulphate is heated in hard glass tube.
- What happens when Zn strip is dipped in CuSO2 solution?
- What is a redox reaction? Write down a chemical reaction representing it.
- In electrolysis of water: Name the gas collected at cathode and anode
- In the reaction: CuO(s) + H2(g) → Cu(s) + H2O (g)
- Give reasons: (a) White silver chloride turns grey in sunlight
- Compound ‘X’ decomposes to form compound ‘Y’ and CO₂ gas. Compound Y is used in the manufacturing of cement.
- A metal salt MX, when exposed to light, splits up to form metal M and gas X₂. Metal M is used to make ornaments whereas gas X₂ is used in making bleaching powder. The salt MX is used in black & white photography.
