chemistry : class11 Reaction Quotient : Equilibrium in chemical processes : Equilibrium MCQ Questions and Answers
Practice important
Reaction Quotient
MCQ questions and answers.
Page 1
of
1
|
10
MCQ Questions
1. For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), what is the expression for the reaction quotient Qc?
A.
Qc = [N2][H2]3/[NH3]2
B.
Qc = [NH3]2/([N2][H2]3)
C.
Qc = [NH3]/([N2][H2])
D.
Qc = [N2][H2]/[NH3]
Correct Answer:
Qc = [NH3]2/([N2][H2]3)
Explanation:
The reaction quotient is written as the product concentrations raised to their stoichiometric coefficients divided by the reactant concentrations raised to their coefficients.
2. For the reaction H2(g) + I2(g) ⇌ 2HI(g), which expression represents Qc?
A.
Qc = [H2][I2]/[HI]2
B.
Qc = [HI]2/([H2][I2])
C.
Qc = [HI]/([H2][I2])
D.
Qc = [H2][I2][HI]2
Correct Answer:
Qc = [HI]2/([H2][I2])
Explanation:
HI is the product and has a coefficient of 2, so its concentration is squared in the numerator. H2 and I2 appear in the denominator.
3. For the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g), if [SO2] = 1 M, [O2] = 1 M, and [SO3] = 2 M, what is Qc?
4. For the reaction CO(g) + H2O(g) ⇌ CO2(g) + H2(g), which expression represents Qc?
A.
Qc = [CO][H2O]/([CO2][H2])
B.
Qc = [CO2][H2]/([CO][H2O])
C.
Qc = [CO2]/([CO][H2O][H2])
D.
Qc = [CO][H2O][CO2][H2]
Correct Answer:
Qc = [CO2][H2]/([CO][H2O])
Explanation:
The products CO2 and H2 are placed in the numerator, while the reactants CO and H2O are placed in the denominator.
5. For the reaction CaCO3(s) ⇌ CaO(s) + CO2(g), which substance is included in the reaction quotient expression?
A.
CaCO3(s) only
B.
CaO(s) only
C.
CO2(g) only
D.
Both CaCO3(s) and CaO(s)
Correct Answer:
CO2(g) only
Explanation:
Pure solids are not included in the reaction quotient expression. Therefore, Qc = [CO2].
6. For a reaction, Qc is less than Kc. What does this indicate about the reaction mixture?
A.
The reaction proceeds mainly in the forward direction
B.
The reaction proceeds mainly in the reverse direction
C.
The reaction has stopped permanently
D.
The reaction quotient must be zero
Correct Answer:
The reaction proceeds mainly in the forward direction
Explanation:
When Qc < Kc, there are relatively more reactants than at equilibrium, so the reaction proceeds forward to form more products.
7. For a reaction, Qc is greater than Kc. In which direction will the reaction proceed to reach equilibrium?
A.
Forward direction
B.
Reverse direction
C.
It will not change
D.
It will proceed equally in both directions
Correct Answer:
Reverse direction
Explanation:
When Qc > Kc, the mixture contains excess products compared with the equilibrium composition, so the reaction shifts in the reverse direction.
8. What is the value of the reaction quotient for a reaction mixture that is already at equilibrium?
A.
Qc = 0
B.
Qc = 1
C.
Qc = Kc
D.
Qc is always greater than Kc
Correct Answer:
Qc = Kc
Explanation:
At equilibrium, the reaction quotient has the same value as the equilibrium constant, so Qc = Kc.
9. For the reaction 2NO2(g) ⇌ N2O4(g), which is the correct expression for Qc?
A.
Qc = [NO2]2/[N2O4]
B.
Qc = [N2O4]/[NO2]2
C.
Qc = [N2O4]2/[NO2]
D.
Qc = [NO2][N2O4]
Correct Answer:
Qc = [N2O4]/[NO2]2
Explanation:
N2O4 is the product and appears in the numerator, while NO2 is the reactant with coefficient 2 and appears squared in the denominator.
10. For the reaction A(g) ⇌ B(g), if [A] = 2 M and [B] = 6 M, what is the reaction quotient Qc?