Chemistry – Multiple Choice Questions (MCQs)

1. 13. What is a chemical bond?

   • A. A physical link between atoms
   • B. The force that holds atoms or ions together in a molecule or crystal
   • C. A temporary attraction between molecules
   • D. A type of nuclear force

2. 14. What is an ionic bond?

   • A. A bond formed by the sharing of electrons
   • B. A bond formed by the electrostatic attraction between oppositely charged ions
   • C. A bond between metal atoms
   • D. A weak bond between polar molecules

3. 15. What is a covalent bond?

   • A. A bond formed by the transfer of electrons
   • B. A bond formed by the sharing of electrons between atoms
   • C. A bond between non-metal atoms only
   • D. A strong bond between ions

4. 16. What is a metallic bond?

   • A. A bond between non-metal atoms
   • B. A bond formed by the attraction between a lattice of positive ions and a 'sea' of delocalized electrons
   • C. A weak bond between metal surfaces
   • D. A bond found only in alloys

5. 17. What is a chemical reaction?

   • A. A physical change in matter
   • B. A process that involves rearrangement of atoms and molecules to form new substances
   • C. Melting of a solid
   • D. Boiling of a liquid

6. 18. What are reactants?

   • A. The substances formed as a result of a chemical reaction
   • B. The substances that undergo a chemical change
   • C. Catalysts that speed up reactions
   • D. Inert gases that do not participate in reactions

7. 19. What are products?

   • A. The substances that undergo a chemical change
   • B. The substances formed as a result of a chemical reaction
   • C. Substances that are unchanged after a reaction
   • D. Substances that inhibit chemical reactions

8. 20. What is a balanced chemical equation?

   • A. An equation where the number of atoms of each element is the same on both sides
   • B. An equation showing only the products
   • C. An equation showing only the reactants
   • D. An equation with equal masses on both sides but not necessarily equal atoms

9. 21. What is oxidation?

   • A. Loss of electrons or an increase in oxidation state
   • B. Gain of electrons or a decrease in oxidation state
   • C. No change in the number of electrons
   • D. Gain of protons

10. 22. What is reduction?

    • A. Gain of electrons or a decrease in oxidation state
    • B. Loss of electrons or an increase in oxidation state
    • C. No change in oxidation state
    • D. Loss of protons

11. 23. What is an acid?

    • A. A substance that tastes bitter
    • B. A substance that releases hydroxide ions (OH-) in water
    • C. A substance that donates protons (H+) or accepts electrons
    • D. A substance with a pH greater than 7

12. 24. What is a base?

    • A. A substance that tastes sour
    • B. A substance that donates protons (H+) in water
    • C. A substance that releases hydroxide ions (OH-) or accepts protons
    • D. A substance with a pH less than 7