Chemical Reactions and Equations MCQ Practice set

 Chemical Reactions and Equations

Q1. Which of the following is a physical change?

A) Cooking of food

B) Ripening of fruit

C) Digestion of food in the stomach

D) Evaporation of water

Q2. Which of the following is a chemical change?

A) Breaking of a glass object on falling from a height

B) Digestion of food in the stomach

C) Evaporation of water

D) Transformation of ice into water

Q3. What is the condensed form of a chemical reaction using chemical formulae called?

A) Chemical equation

B) Reactant equation

C) Balanced equation

D) Word equation

Q4. In a chemical equation, the reactants are written on the _______.

A) Right-hand side

B) Top side

C) Left-hand side

D) Bottom side

Q5. How are the reactants and products linked in a chemical equation when there are two or more?

A) Arrow pointing downwards

B) Equals sign (=)

C) Minus sign (-)

D) Plus sign (+)

Q6. In balancing the equation NaOH + H2SO4 → Na2SO4 + H2O, which element is selected first for balancing?

A) Oxygen (O)

B) Hydrogen (H)

C) Sodium (Na)

D) Sulphur (S)

Q7. Which law of chemistry is followed when the total mass of each element in the reactants is equal to the total mass of each element in the products?

A) Law of conservation of mass

B) Law of conservation of energy

C) Law of conservation of momentum

D) Law of constant composition

Q8. A balanced equation has the same number of atoms for each element in the _______.

A) Products

B) Reactants

C) Both reactants and products

D) None of the above

Q9. Which type of chemical reaction involves the combination of two or more reactants to form a single product?

A) Decomposition reaction

B) Combination reaction

C) Acid-base reaction

D) Redox reaction

Q10. How many reactants are involved in a decomposition reaction?

A) two

B) Three

C) One

D) Four

Q11. Which reaction involves the breakdown of a single reactant into two or more products?

A) Combination reaction

B) Decomposition reaction

C) Neutralization reaction

D) Precipitation reaction

Q12.In the reaction between copper sulfate (CuSO4) and iron (Fe), what are the products formed?
CuSO4(aq) + Fe(s) → ?

A) Cu(s) + Fe2(SO4)3(aq)

B) Cu2SO4(aq) + Fe(s)

C) CuSO4(s) + Fe2O3(s)

D) Cu(s) + FeSO4(aq)

Q13.What is the color of the precipitate formed when potassium chromate (K2CrO4) is added to a solution of barium sulphate (BaSO4)?

A) White

B) Blue

C) Yellow

D) Green

Q14. Which of the following is an exothermic process?

A) Formation of ice from water

B) Dissolution of sodium hydroxide in water

C) Dissolution of potassium nitrate in water

D) Melting of ice

Q15. The rate of a chemical reaction increases when the size of the particles of the reactants:

A) Increases

B) Decreases

C) Remains the same

D) Has no effect

Q16. What is a catalyst in a chemical reaction?

A) A substance that increases the rate of a reaction without undergoing a chemical change

B) A substance that undergoes a chemical change during the reaction

C) A substance that increases the concentration of reactants

D) A substance that decreases the rate of a reaction

Q17. Which of the following statements about oxidation reactions is correct?

A) A reactant combines with oxygen.

B) A reactant loses hydrogen.

C) A reactant gains oxygen.

D) All of the above.

Q18. In the reaction 2KMnO4 + 10FeSO4 + 8H2SO4 -> K2SO4 + 2MnSO4 + 5Fe2(SO4)3 + 8H2O, which compound is oxidized?

A) KMnO4

B) K2SO4

C) FeSO4

D) MnSO4

Q19. The net ionic reaction for the oxidation of ferrous ion (Fe2+) to ferric ion (Fe3+) is represented as:

A) Fe3+ -> Fe2+ + 2e-

B) Fe2+ + 2e- -> Fe3+

C) Fe2+ -> Fe3+ + 2e-

D) Fe2+ + Fe3+ -> Fe3+

Q20. Which of the following is a correct definition of oxidation?

A) A reactant loses one or more electrons.

B) A reactant combines with oxygen.

C) A reactant gains hydrogen.

D) A reactant gains oxygen

Q21. When the positive charge on an atom or an ion increases or the negative charge on them decreases, it is called:

A) Oxidation

B) Reduction

C) Redox

D) None of the above

Q22. Which enzyme is involved in the transport of electrons during cellular respiration?

A) Cytochrome C oxidase

B) Reductase

C) Oxidase

D) Catalase

Q23. Which of the following reactions represents the formation of rust?

A) O2 (g) + 4H+ (aq) + 4e- → 2H2O (l)

B) Fe2+ (aq) + 4H2O (l) → Fe2O3·H2O (s) + 4H+ (aq)

C) Fe2+ (aq) + 2e- → Fe (s)

D) Fe (s) + O2 (g) → FeO (s)

Q24. Corrosion is a process that primarily affects:

A) Silver

B) Brass

C) Iron

D) Aluminum

Q25. Rancidity in cooking oil or ghee is prevented by:

A) Storing in an airtight container

B) Exposing to sunlight

C) Boiling the oil or ghee

D) Adding antioxidants

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