Q1) What is chemical equilibrium?

a) A state in which the forward and reverse reactions occur at the same rate

b) A state where the concentration of reactants is zero

c) A state in which only the forward reaction occurs

d) A state where the concentration of products is maximum

Q2) Which factor does NOT affect the position of equilibrium?

a) Temperature

b) Pressure

c) Concentration

d) Catalyst

Q3) What happens to the rate of the forward and reverse reactions at equilibrium?

a) The rates become equal

b) The rates of both reactions stop

c) The rate of the forward reaction increases

d) The rate of the reverse reaction increases

Q4) Which principle states that if a system at equilibrium is disturbed, it will adjust to counteract the disturbance?

a) Avogadro's Principle

b) Boyle's Law

c) Le Chatelier's Principle

d) Gay-Lussac's Law

Q5) In which direction does the equilibrium shift if the pressure of a gaseous reaction is increased?

a) Toward the side with fewer moles of gas

b) Toward the side with more moles of gas

c) It does not shift

d) It shifts randomly

Q6) The equilibrium constant expression (Kc) for the reaction: A + 2B ⇌ 3C is:

a) [C]^3 / [A][B]^2

b) [A][B]^2 / [C]^3

c) [C] / [A][B]^2

d) [A][B]^2 / [C]

Q7) What does it mean if the equilibrium constant (Kc) for a reaction is very large?

a) The reaction favors the products

b) The reaction favors the reactants

c) The reaction has reached completion

d) The reaction does not reach equilibrium

Q8) What happens to the equilibrium constant (Kc) if the reaction is reversed?

a) It remains the same

b) It becomes the reciprocal

c) It doubles

d) It becomes zero

Q9) Which of the following changes would shift the equilibrium of the reaction N2(g) + 3H2(g) ⇌ 2NH3(g) to the right?

a) Decreasing the pressure

b) Increasing the pressure

c) Removing NH3(g)

d) Adding N2(g)

Q10) How does increasing the temperature affect an endothermic reaction at equilibrium?

a) Shifts equilibrium to the left

b) Shifts equilibrium to the right

c) Does not affect equilibrium

d) Depends on the concentration of reactants

Q11) Which of the following would increase the equilibrium constant (Kc) for a reaction?

a) Increasing the concentration of reactants

b) Decreasing the temperature

c) Adding a catalyst

d) Increasing the pressure

Q12) What happens to the equilibrium constant (Kc) if the coefficients in the balanced equation are multiplied by a factor?

a) Kc remains the same

b) Kc is divided by the factor

c) Kc is multiplied by the factor

d) Kc becomes zero

Q13) If Q < Kc, what does it indicate about the reaction mixture?

a) Reaction is at equilibrium

b) Reaction favors the products

c) Reaction favors the reactants

d) Reaction has not reached equilibrium

Q14) What is the value of the equilibrium constant (Kc) for a reaction when the concentrations of products and reactants are equal?

a) 0

b) 1

c) Infinity

d) Cannot be determined

Q15) Which of the following is NOT a way to express the equilibrium constant (Kc)?

a) Ratio of product concentrations to reactant concentrations

b) Ratio of product pressures to reactant pressures

c) Ratio of product molarities to reactant molarities

d) Ratio of product masses to reactant masses

Q16) What is the effect of adding an inert gas at constant volume to a system at equilibrium?

a) Shifts equilibrium to the left

b) Shifts equilibrium to the right

c) Does not affect equilibrium

d) Depends on the type of inert gas

Q17) What is the unit of equilibrium constant (Kc) for a homogeneous gas-phase reaction?

a) M

b) M^2

c) M^-1

d) Dimensionless

Q18) What is the equilibrium constant expression (Kc) for the reaction: 2NOCl(g) ⇌ 2NO(g) + Cl2(g)?

a) [NO]^2[Cl2] / [NOCl]^2

b) [NO][Cl2] / [NOCl]^2

c) [NO][Cl2] / [NOCl]

d) [NO][Cl2]^2 / [NOCl]^2

Q19) If a catalyst is added to a reaction at equilibrium, what effect does it have on the position of equilibrium?

a) It shifts the equilibrium to the left

b) It shifts the equilibrium to the right

c) It does not affect the position of equilibrium

d) It increases the equilibrium constant (Kc)

Q20) Which statement about equilibrium is correct?

a) Equilibrium is only achieved in closed systems.

b) Equilibrium is achieved when all reactants are consumed.

c) Equilibrium can only be reached in irreversible reactions.

d) Equilibrium can be established in both physical and chemical processes.