Free Chemical Equilibrium MCQs with Answers
625 Chemical Equilibrium MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Reversible reactions reach dynamic equilibrium when forward and reverse rates become equal, and Le Chatelier's principle predicts the effect of changing concentration, pressure or temperature. The chapter also covers solubility product, the common ion effect, buffer action and the conditions used in Haber's process, with equilibrium shifts distinguished from changes in the equilibrium constant.
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625 questions · page 31 of 32
- A. Very difficult step
- B. Highly unstable product
- C. Highly endothermic
- D. None of the above
Explanation: The Haber process involves the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2) gases.
Correct answer: Highly endothermic- A. A decrease in the volume of the container .
- B. An increase pressure by addition of hydrogen
- C. Removal of NH3
- D. An increase in pressure by addition.of nitrogen
Explanation: To do such questions, Your concepts about the Le Chatelier principle must be clear and you must know how to apply that.
Correct answer: An increase in pressure by addition.of nitrogen603. In the given Exothermic reaction PCl3 + Cl2 (g) ➔PCl5(g) an increase in yield will be favoured by:
- A. Decrease of temperature
- B. Increase of temperature
- C. Keeping temperature constant
- D. None of these
Explanation: Since the forward reaction is exothermic, decreasing the temperature will cause the reaction to shift in the forward direction by Le…
Correct answer: Decrease of temperature- A. Both pressure and temperature are increased
- B. Both pressure and temperature are decreased
- C. Temperature is decreased and pressure is increased
- D. Temperature is increased and pressure is increased
Explanation: The reaction 2SO2 + O2 → 2SO3 is exothermic, releasing heat. According to Le Chatelier's principle, increasing pressure shifts the…
Correct answer: Temperature is decreased and pressure is increased- A. Is independent of temperature
- B. Increases as temperature increases
- C. Decreases as temperature increases
- D. Varies with the addition of N2 and O2
Explanation: In general, for an exothermic reaction, the reaction rate decreases as the temperature increases.
Correct answer: Decreases as temperature increases- A. Increase in temperature
- B. Decrease in temperature
- C. No change in temperature
- D. First increase and then decrease in temperature
Explanation: Increasing the temperature of the system provides more heat energy to the reaction, which helps drive the reaction toward the reactant side.
Correct answer: Increase in temperature- A. Endothermic process
- B. Exothermic process
- C. Vaporization process
- D. Change of H2O into O2 and H2
Explanation: The ionic product of water (Kw) is the product of the concentrations of hydrogen ions (H+) and hydroxide ions (OH-) in water.
Correct answer: Endothermic process- A. The equilibrium will shift in the backward direction
- B. The equilibrium position will remain unchanged
- C. The equilibrium will shift in the forward direction
- D. All of the above
Explanation: In an endothermic reaction such as N2(g) + O2(g) → 2NO(g), increasing the temperature provides additional heat that the system can absorb.
Correct answer: The equilibrium will shift in the forward direction- A. Forward direction
- B. Reverse direction
- C. To all system at equilibrium
- D. None of the above
Explanation: By increasing the pressure, the equilibrium between ice and water will shift in the direction of the phase with the lower volume, which is…
Correct answer: Forward direction- A. remains constant
- B. increase
- C. decrease
- D. varies
Explanation: When the pressure of a gaseous mixture in equilibrium increases at constant temperature, the equilibrium constant remains constant.
Correct answer: remains constant- A. 0.05
- B. 0.25
- C. 0.35
- D. 0.45
Explanation: Partial pressure = moles of substance/total moles * total pressure =moles of N2/total moles * total pressure =1/4 * 1 atm = 0.25
Correct answer: 0.25- A. dimension (i.e., with no unit)
- B. mole dm3
- C. mole dm-3
- D. mole2 dm3
Explanation: The correct unit for the reaction N2O4 g → 2NO2 g is mole dm-3, as it represents the concentration of the substances involved in the…
Correct answer: mole dm-3- A. Glass vessel
- B. Iron vessel
- C. Open vessel
- D. Closed vessel
Explanation: At equilibrium, the rate of forward reaction equals the rate of reverse reaction.
Correct answer: Closed vessel- A. When forward and backward reaction taking place at the same rate
- B. Reaction takes place
- C. The forward and backward
- D. There are two reactions with one faster than the other
Explanation: At equilibrium, the rates of the forward and backward reactions are equal, and there is no net change in the concentrations of the…
Correct answer: When forward and backward reaction taking place at the same rate- A. Is the same at different temperature?
- B. Is different at different temperature
- C. Is negligible at room temperature
- D. Can be same at different temperatures
Explanation: The value of K (equilibrium constant) for a reaction can be different at different temperatures.
Correct answer: Is different at different temperature- A. Kc is very large
- B. Kc is very small
- C. Kc is neither very small nor very large
- D. Kc is equal to 1
Explanation: The reaction given is:2Cl(g) \rightleftharpoons Cl_2(g)The equilibrium constant, K_c, is defined as the ratio of the concentrations of the…
Correct answer: Kc is very large- A. Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+]
- B. Kc = [Ce3+][Fe2+]/[Ce4+][Fe3+]
- C. Kc = [Ce4+][Fe3+]/[Ce3+][Fe2+]
- D. Kc = [Ce3+][Fe2+][Ce4+][Fe3+]
Explanation: The correct equilibrium constant expression, Kc, for the given reaction is Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+].
Correct answer: Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+]- A. Raoult's Law
- B. Le Chatelier's Principle
- C. The law of conservation of energy
- D. The law of mass action
Explanation: The correct answer is the law of mass action. This law specifically states that the rate of a chemical reaction is proportional to the…
Correct answer: The law of mass action- A. Kp = Kc
- B. Kp < Kc
- C. Kp > Kc
- D. Kp < 0
Explanation: Kp and Kc are equilibrium constants for reactions involving gases. Kp is used when partial pressures are involved, while Kc is used for…
Correct answer: Kp < Kc- A. Conversion of A to B is 50% complete
- B. 50% reactant has been changed to B
- C. Rate of transformation of A to B is equal to B to A
- D. Complete conversion of A to B has taken place
Explanation: When a chemical reaction is in equilibrium, it means that the rate at which A transforms into B is equal to the rate at which B transforms…
Correct answer: Rate of transformation of A to B is equal to B to A