Chemical equilibrium, equilibrium constants Kp and Kc, Le Chatelier's principle, ionic equilibrium, acids and bases concepts, pH scale, buffers and solubility products - Question Bank

1. If the ionic product of a solution is less than its Ksp, the solution is:
A) Unsaturated
B) Saturated
C) Supersaturated
D) At equilibrium
2. The pH of a 0.001 M NaOH solution is:
A) 3
B) 11
C) 14
D) 1
3. For the equilibrium CaCO3(s) <=> CaO(s) + CO2(g), if the pressure of CO2 is increased, the equilibrium will:
A) Shift to the left
B) Shift to the right
C) Remain unchanged
D) The equilibrium constant will increase
4. Which of the following species can act as both a Brønsted-Lowry acid and a Brønsted-Lowry base?
A) H2SO4
B) OH-
C) NH3
D) HCO3-
5. The solubility of a salt is defined as:
A) The maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature.
B) The rate at which a solute dissolves.
C) The equilibrium concentration of the dissolved solute.
D) The total amount of solute present in a solution.
6. A buffer solution prepared from a weak base and its conjugate acid will have its pH calculated using:
A) pH = pKa + log([base]/[acid])
B) pOH = pKb + log([conjugate acid]/[base])
C) pH = pKb + log([base]/[acid])
D) pOH = pKa + log([acid]/[base])
7. If Kp > Kc for a reversible reaction, it implies that:
A) Δn > 0 (change in moles of gas is positive)
B) Δn < 0 (change in moles of gas is negative)
C) Δn = 0 (change in moles of gas is zero)
D) The reaction is exothermic
8. The Ksp of Mg(OH)2 is 1.8 x 10^-11. The solubility of Mg(OH)2 in pure water is:
A) 2.6 x 10^-4 M
B) 1.3 x 10^-4 M
C) 1.8 x 10^-11 M
D) 3.6 x 10^-11 M
9. Which of the following is an amphoteric substance?
A) HCl
B) NaOH
C) H2O
D) NH3
10. In an ionic equilibrium, the degree of dissociation of a weak electrolyte is:
A) Directly proportional to the square root of dilution
B) Inversely proportional to the square root of dilution
C) Independent of dilution
D) Directly proportional to dilution
11. For the reaction SO2Cl2(g) <=> SO2(g) + Cl2(g), if the pressure is increased by doubling the volume, the equilibrium will:
A) Shift to the left
B) Shift to the right
C) Remain unchanged
D) The equilibrium constant will change
12. What is the concentration of H+ ions in a solution with pH = 5?
A) 10^-5 M
B) 5 M
C) 10^5 M
D) 0.5 M
13. The Lewis acid-base reaction involves the transfer of:
A) A proton
B) An electron pair
C) A neutron
D) An electron
14. Which of the following will decrease the solubility of AgCl in water?
A) Adding NaCl solution
B) Adding AgNO3 solution
C) Adding pure water
D) Heating the solution
15. The solubility of CaF2 is 's' mol/L. Its solubility product Ksp is:
A) 4s^3
B) s^2
C) s^4
D) 2s
16. A buffer solution of acetic acid and sodium acetate has a pH of 4.75. If Ka for acetic acid is 1.8 x 10^-5, what is the ratio of [CH3COO-]/[CH3COOH]?
A) 1:1
B) 1:2
C) 2:1
D) 10:1
17. The pH of a 0.01 M HCl solution is:
A) 1
B) 2
C) 12
D) 13
18. Which of the following is a strong base?
A) NH3
B) NaOH
C) CH3COOH
D) H2O
19. The ionization constant of a weak acid (Ka) is:
A) The equilibrium constant for its dissociation
B) The equilibrium constant for its association
C) The solubility product
D) The concentration of H+ ions
20. For the reaction 2SO2(g) + O2(g) <=> 2SO3(g) (exothermic), if temperature is decreased, equilibrium will:
A) Shift to the left
B) Shift to the right
C) Remain unchanged
D) The rate of reaction will decrease
21. The equilibrium constant Kp is defined in terms of:
A) Molar concentrations
B) Partial pressures
C) Mole fractions
D) Total pressure
22. Which factor does NOT affect the equilibrium position of a gaseous reaction?
A) Temperature
B) Pressure
C) Concentration of reactants/products
D) Addition of an inert gas at constant volume
23. A solution with a pOH of 2 is:
A) Acidic
B) Basic
C) Neutral
D) Strongly acidic
24. For the equilibrium CO(g) + H2O(g) <=> CO2(g) + H2(g), if the concentration of CO is increased, the equilibrium will:
A) Shift to the left
B) Shift to the right
C) Remain unchanged
D) The equilibrium constant will decrease
25. The conjugate base of H2SO4 is:
A) HSO4-
B) SO4^2-
C) H3O+
D) OH-
26. Which of the following is an example of a Lewis acid?
A) BF3
B) NH3
C) H2O
D) OH-
27. The autoionization of water produces:
A) H+ and OH- ions
B) H3O+ and OH- ions
C) Only H+ ions
D) Only OH- ions
28. The common ion effect states that the solubility of a sparingly soluble salt is decreased by the presence of:
A) A common ion
B) An ion not common to the salt
C) Water
D) An acid
29. If the ionic product of a solution is greater than its Ksp, then:
A) Precipitation will occur
B) No precipitation will occur
C) The solution is unsaturated
D) The salt is highly soluble
30. The solubility product (Ksp) of a sparingly soluble salt like AgCl is:
A) [Ag+][Cl-]
B) [Ag+][Cl-]/[AgCl]
C) [Ag+]/[Cl-]
D) [Ag+] + [Cl-]
31. The Henderson-Hasselbalch equation for a weak acid buffer is:
A) pH = pKa + log([conjugate base]/[acid])
B) pH = pKa + log([acid]/[conjugate base])
C) pOH = pKb + log([conjugate acid]/[base])
D) pH = pKa - log([acid]/[conjugate base])
32. A buffer solution is typically made from a mixture of:
A) A strong acid and its conjugate base
B) A strong base and its conjugate acid
C) A weak acid and its conjugate base
D) A weak base and its conjugate acid
33. A buffer solution resists changes in pH upon addition of small amounts of:
A) Strong acid or strong base
B) Weak acid or weak base
C) Salt
D) Water
34. Which of the following is a conjugate acid-base pair?
A) H2O and OH-
B) HCl and Cl-
C) NH3 and NH4+
D) All of the above
35. For a strong acid like HCl, its dissociation in water is:
A) Partial
B) Complete
C) Reversible
D) Slow
36. What is the pOH of a solution with a pH of 10?
A) 4
B) 10
C) 14
D) 0
37. A solution with a pH of 3 is considered:
A) Acidic
B) Basic
C) Neutral
D) Amphoteric
38. The pH of a neutral solution at 25°C is:
A) 0
B) 7
C) 14
D) 1
39. A Brønsted-Lowry base is defined as a species that:
A) Accepts a proton
B) Donates a proton
C) Donates an electron pair
D) Accepts an electron pair
40. According to Arrhenius theory, an acid is a substance that:
A) Donates a proton (H+)
B) Accepts a proton (H+)
C) Dissociates in water to produce H+ ions
D) Dissociates in water to produce OH- ions
41. Which of the following is a characteristic of ionic equilibrium?
A) It involves reactions between ions in solution.
B) It only occurs in non-polar solvents.
C) It does not involve dynamic processes.
D) It is always fast.
42. Adding a catalyst to a reversible reaction at equilibrium:
A) Shifts the equilibrium to the right.
B) Shifts the equilibrium to the left.
C) Increases the rate of both forward and reverse reactions equally, reaching equilibrium faster.
D) Decreases the equilibrium constant.
43. The relationship between Kp and Kc for the reaction N2(g) + 3H2(g) <=> 2NH3(g) is:
A) Kp = Kc(RT)^-2
B) Kp = Kc(RT)^2
C) Kp = Kc
D) Kp = Kc(RT)
44. For an endothermic reaction at equilibrium, if the temperature is increased, the equilibrium will:
A) Shift to the left
B) Shift to the right
C) Remain unchanged
D) The equilibrium constant will decrease
45. Le Chatelier's principle applies to:
A) Systems at equilibrium
B) Systems not at equilibrium
C) Only gaseous reactions
D) Only exothermic reactions
46. Which of the following is a unit of Kc for the reaction H2(g) + I2(g) <=> 2HI(g)?
A) mol/L
B) mol^-1 L
C) mol L^-1
D) Unitless
47. For the reaction PCl5(g) <=> PCl3(g) + Cl2(g), if the volume of the container is decreased, the equilibrium will:
A) Shift to the left
B) Shift to the right
C) Remain unchanged
D) The equilibrium constant will increase
48. The equilibrium constant Kc for the reaction aA + bB <=> cC + dD is given by:
A) ([C]^c [D]^d) / ([A]^a [B]^b)
B) ([A]^a [B]^b) / ([C]^c [D]^d)
C) ([C]^c + [D]^d) / ([A]^a + [B]^b)
D) ([C]^c [D]^d) * ([A]^a [B]^b)
49. In the equilibrium N2(g) + 3H2(g) <=> 2NH3(g), if the partial pressure of N2 is increased, what will happen to the equilibrium?
A) Shift to the left (towards reactants)
B) Shift to the right (towards products)
C) No change
D) The equilibrium constant will change
50. For a reversible reaction, which statement is always true at equilibrium?
A) The rate of the forward reaction is equal to the rate of the reverse reaction.
B) The concentrations of reactants and products are equal.
C) The reaction has stopped.
D) The temperature and pressure are constant.