30 Chemical Equilibrium Practice Problems for DAT Prep

IX. Chemical Equilibrium

Chemical equilibrium practice problems

There are a total of 30 chemical equilibrium practice problems, which are important content-oriented in the summary part of this chapter. Approximately 1 minute is given per question in each test. After the test, if you press the “See Result” button, the results will be displayed along with the answer choices. Red marks indicate incorrect answers and green marks indicate correct answers. Explanations or solutions to the questions are displayed below each question.

CHEMICAL EQUILIBRIUM TEST 1

1 / 20

Which of the following is a reversible reaction?

A. 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l)

B. 4HNO₃(aq) + Cu(s) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

C. LiOH(aq) + HI(aq) → Li(aq) + H₂O(l)

D. Pb(NO₃)₂(aq) + 2KI(aq) → 2KNO₃(aq) + PBI₂(s)

E. CH₄(g) + H₂O(g) → CO(g) + 3H₂(g)

Explanation:

A, B, C, and D are irreversible reactions, which are the combustion reaction, gas production from the reaction between an acid and a metal, neutralization between a strong acid and a strong base, and precipitation reaction.

2 / 20

Which of the following is a correct statement about the equilibrium state of a reaction?

A. The equilibrium state is seen in both reversible and irreversible reactions.

B. At equilibrium, the rate of a forward reaction is faster than in a reverse reaction.

C. At equilibrium, both the forward and reverse reactions are stopped.

D. At equilibrium, the concentration of the reactant and the product is constant.

E. At equilibrium, the concentration of the reactant and the product is the same.

Explanation:

The equilibrium state is seen only in a reversible reaction and the rate of a forward and reverse reaction is the same. The forward and reverse reaction does not stop but the reaction rate remains constant. The concentration of the reactant and the product is not the same, but the concentration of the reactant and the product is constant.

3 / 20

Which of the following affects the equilibrium constant K_eq?

A. Concentration of reactants or products

B. Temperature

C. Catalysis

D. Reaction quotient (Q)

E. B and C

Explanation:

The equilibrium constant K_eq depends only on the temperature.

4 / 20

Which of the following is an INCORRECT statement?

A. Keq > 1 means that there are more products than reactants.

B. Solids and pure liquids are not considered for the equilibrium equation.

C. Keq < 1 means that the forward reaction has not occurred.

D. Keq = Q represents the equilibrium state of a reaction.

E. The equilibrium depends on ΔG.

Explanation:

K_eq < 1 means that the forward reaction is predominant and both forward and reverse reaction have occurred.

5 / 20

Explanation:

The equilibrium constant K_c applies to a reaction of aqueous solution and gas.

6 / 20

A. 1/2 M

B. 1 M

C. 2 M

D. 4 M

E. 1/4 M

Solution:

K_c = [H₂]²[O₂]

8 = (x)²(2)

x = 2

7 / 20

A. 0.67

B. 1

C. 2

D. 4

E. 8

Solution:

8 / 20

Solution:

The equilibrium constant K_p applies to a gas reaction.

9 / 20

A. 6

B. 12

C. 18

D. 24

E. 48

Solution:

10 / 20

A. Removing H₂

B. Adding C

C. Adding H₂O

D. Removing C

E. Both removing H₂ and adding H₂O

Solution:

11 / 20

A. Decreasing volume

B. Decreasing temperature

C. Increasing pressure

D. Adding H₂O

E. Removing NH₃

Explanation:

12 / 20

A. Adding O₂

B. Removing O₃

C. Increasing pressure

D. Decreasing temperature

E. All shift the reaction forward.

Explanation:

Adding O₂, removing O₃, and increasing pressure make the reaction move forward. Because this reaction is exothermic, decreasing the temperature shifts the reaction forward.

13 / 20

A. NH₃

B. NH₄⁺

C. F^–

D. NH₃ and F^–

E. HF and NH₄⁺

Explanation:

Conjugate acid-base pairs are formed by transferring one proton. The conjugate base from the acid HF is F^–.

14 / 20

A. The reaction I is processed from left to right.

B. F- is a Bronsted-Lowry base.

C. HF and BF3 are Lewis bases.

D. Reaction I could be explained as an example of an Arrhenius base.

E. Reactions I and II is an example of a Lewis acid.

Explanation:

The reaction I is processed from right to left because HBr is a strong acid. F^– is a Lewis base, which can donate an electron-pair. HF and BF₃ are Lewis acids, which can receive an electron-pair. An Arrhenius base could be seen in a reaction that produces OH^– in H₂O. The concepts of Lewis acid and base involve the concepts of Bronsted-Lowry and Arrhenius.

15 / 20

Which of the following CANNOT be a Bronsted-Lowry base?

A. H₂PO₄^–

B. NH₃

C. Cl^–

D. H₂O

E. BeCl₂

Explanation:

A Bronsted-Lowry base is a substance that can receive H⁺. H₂PO₄^–, NH_3,Cl^–, and BeCl₂ can receive H⁺ to be H₃PO₄, NH₄⁺, HCl, H₃O⁺. However, BeCl₂cannot receive H⁺.

16 / 20

Which of the following is a correct comparison of acid strength?

A. H₂O > HF

B. HCl > HBr

C. HOCl > HOBr

D. HOClO₂ > HOClO₃

E. CH₃CO₂H > H₂SO₄

Explanation:

H₂O < HF : binding with hydrogen, CH₄ < NH₃ < H₂O < HF

HCl < HBr : binding with hydrogen, HF < HCl < HBr < HI

HOCl > HOBr : binding with hydro oxygen, HOI < HOBr < HOCl

HOClO₂ < HOClO₃ : binding with oxygen numbers, HOCl < HOClO < HOClO₂ < HOClO₃

CH₃CO₂H < H₂SO₄ : strong acid (HCl, HBr, HI, HClO₄, H₂SO₄, HNO₃), weak acid (H₃PO₄, CH₃CO₂H, HF, HCN)

17 / 20

Which of the following is the strongest base?

A. Ba(OH)₂

B. NH₃

C. CH₃NH₂

D. NO₃^–

E. HClO₄

Explanation:

18 / 20

Which of the following is the correct expression for the equilibrium constant K_a for the dissociation of HCl in water?

Explanation:

19 / 20

0.02M NH₃ is dissociated in a solution. When the K_b for NH₃ is 1.8×10^-5, what is the concentration of OH^–?

A. 3.0×10^-4 M

B. 6.0×10^-4 M

C. 1.2×10^-3 M

D. 1.8×10^-3 M

E. 3.6×10^-3 M

Solution:

20 / 20

0.05M H₂SO₄ is dissociated in a solution. What is the concentration of OH^–?

A. 1.0×10^-12

B. 2.0×10^-13

C. 1.0 × 10^-14

D. 3.0×10^-15

E. 5.0×10^-16

Solution:

Your score is

The average score is 41%

CHEMICAL EQUILIBRIUM TEST 2

1 / 10

What is the pH of solution containing [OH^–] = 4.0×10^-11?

A. 3.0

B. 3.5

C. 4.0

D. 4.5

E. 5.0

Solution:

2 / 10

48g of LiOH is dissolved in 4L of solution. What is the pH of the solution?

A. 0.5

B. 4.5

C. 9.0

D. 11.5

E. 13.5

Solution:

3 / 10

K_a of HNO₂ is 4.5×10^-4. When 0.00001 moles of HNO₂ solution is diluted in a 5L vessel, find the pH of the solution.

A. 3.0

B. 3.5

C. 4.0

D. 4.5

E. 5.0

Solution:

4 / 10

In a buffer solution a weak acid is 99% dissociated. When the pH is 6.5, what is the value of pKa?

A. 4.0

B. 4.5

C. 5.0

D. 5.5

E. 6.0

Solution:

5 / 10

A. [Ag⁺][2SO₄^2-]

B. [2Ag⁺][SO₄^2-]

C. [Ag⁺][SO₄^2-]²

D. [Ag⁺]²[SO₄^2-]

E. [Ag⁺]²[SO₄^2-]⁴

Solution:

6 / 10

When the molar solubility is expressed by X, choose the correct equation of the solubility product K_sp for saturated solution of CaF₂.

A. Ksp = [X][X]²

B. Ksp = [X][2X]²

C. Ksp = [X]²[2X]

D. Ksp = [2X][X]

E. Ksp = [2X]²[2X]

Solution:

7 / 10

What is the molar solubility of Chromium(III) hydroxide, Cr(OH)₃, when K_sp of Cr(OH)₃ is 2.7×10^-27 at 20^oC.

A. 1 × 10^-7 M

B. 3 × 10^-7 M

C. 6 × 10^-6 M

D. 1 × 10^-5 M

E. 3 × 10^-5 M

Solution:

8 / 10

What is the concentration of Cu²⁺ in Cu₃(PO₄)₂when K_spof the saturation solution Cu₃(PO₄)₂is 1.08×10^-28?

A. 3×10^-5 M

B. 1×10^-6 M

C. 2×10^-6 M

D. 3×10^-6 M

E. 2×10^-7 M

Solution:

9 / 10

What is the K_sp for saturated solution Al(OH)₃ when the concentration of aluminum ions is 2.0 × 10^-5M?

A. 4.0× 10^-10

B. 2.7 × 10^-18

C. 4.3×10^-18

D. 8.6 × 10^-16

E. 2.0 × 10^-20

Solution:

10 / 10

Which of the following is an INCORRECT statement?

A. K_c > 1 means that there is a predominance of product in the reaction.

B. K_c< Q means that the reaction moves from right to left.

C. IP < K_sp means that precipitation occurs in an ionic solution.

D. Decreasing K_sp means increasing the freezing point.

E. Increasing K_sp means increasing the electrical conduction.

Explanation:

IP < K_sp means that a precipitation does not occur in an ionic solution.

Your score is

The average score is 28%

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