10th class Chemistry, Chapter 17: Reaction Kinetics MCQs

1. The number of collisions per unit volume of the reaction mixture is called:

1. (A) Collision energy
2. (B) Activation energy
3. (C) Collision frequency ✓
4. (D) Collision force

2. If the reactants possess an energy higher than the activation energy, then the reaction will be:

1. (A) Slow
2. (B) Fast ✓
3. (C) Not affected
4. (D) Instantaneous

3. Which of the following explains the increase in rate of reaction in the presence of a catalyst?

1. (A) Catalyst provides extra energy to the reactant molecules
2. (B) Catalyst provides an alternative pathway which lowers the activation energy. ✓
3. (C) Catalyst increases the collision frequency
4. (D) Catalyst decreases the collision frequency

4. Which of the following statements is correct?

1. (A) Collisions with energy equal to or greater than the activation energy lead to reaction. ✓
2. (B) Collision frequency is not related to the reaction rate
3. (C) All collisions lead to a reaction.
4. (D) Collisions with energy less than the activation energy lead to the reaction.

5. When a reaction proceeds ahead, how the concentrations of reactants and products change?

1. (A) Concentration of reactants increases and that of the products decreases.
2. (B) Concentration of reactants decreases and that of the products increases. ✓
3. (C) Concentration of both reactants and products decreases.
4. (D) Concentration of both reactants and products increases.

6. A reaction takes place only when the reacting particles:

1. (A) are heated
2. (B) are dissolved
3. (C) are separated
4. (D) collide with one another ✓

7. Collisions which lead to reaction are called:

1. (A) elastic collisions
2. (B) effective collisions ✓
3. (C) weak collisions
4. (D) random collisions

8. A very small fraction of collisions lead to the formation of:

1. (A) energy
2. (B) catalyst
3. (C) reactants
4. (D) products ✓

9. Higher concentration of reactants means:

1. (A) slower particles
2. (B) fewer collisions
3. (C) no collisions
4. (D) more collisions ✓

10. At higher temperature the velocities of molecules:

1. (A) increase ✓
2. (B) decrease
3. (C) become zero
4. (D) remain the same

11. The minimum energy required to start a chemical reaction is called:

1. (A) activation energy ✓
2. (B) kinetic energy
3. (C) potential energy
4. (D) heat energy

12. When the reactant particles come close during collision, their kinetic energy is converted to:

1. (A) sound
2. (B) potential energy ✓
3. (C) light
4. (D) heat only

13. The total mass during a chemical reaction always:

1. (A) increases
2. (B) remains the same ✓
3. (C) decreases
4. (D) becomes zero

14. Burning of Mg ribbon in an open crucible gives a product heavier than Mg because Mg reacts with:

1. (A) water
2. (B) nitrogen
3. (C) hydrogen
4. (D) oxygen of the air ✓

15. When marble chips react with dilute HCl in an open container, the apparent mass:

1. (A) doubles
2. (B) increases
3. (C) stays the same
4. (D) decreases because CO₂ escapes ✓

16. In exothermic reactions the surroundings:

1. (A) cool down
2. (B) get heated ✓
3. (C) freeze
4. (D) remain the same

17. Dissolving ammonium chloride or ammonium nitrate in water is:

1. (A) endothermic ✓
2. (B) exothermic
3. (C) neutral
4. (D) explosive

18. Quick lime (CaO) reacts with water to give:

1. (A) Ca(OH)₂ ✓
2. (B) Ca
3. (C) CaCO₃
4. (D) CaCl₂

19. For many reactions the rate doubles for every ____ rise in temperature.

1. (A) 1 °C
2. (B) 5 °C
3. (C) 10 °C ✓
4. (D) 100 °C

20. Coal burns faster in pure oxygen than in air because air contains only ____ oxygen.

1. (A) 50%
2. (B) 21% ✓
3. (C) 78%
4. (D) 1%