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| Chemistry 11th Chapter 8 Chemical Equilibrium Questions Bank |
Chemistry 1st Year Chapter 8 Chemical Equilibrium Questions Bank
MCQs
Please select the right answer.
1. What will be the pH of 1.0 mol dm⁻³ of H₂X, which is only 50% dissociated?
2. A basic buffer solution can be prepared by mixing:
3. A solution having zero pH value will be:
4. Almost forward reaction is complete when:
5. An excess of silver nitrate is added to the aqueous barium chloride and the precipitate is removed by filtration. What are the main ions in the filtrate?
6. At equilibrium, the concentration of reactants and products are:
7. Buffer action can be explained by except?
8. Buffer action can be explained by:
9. Buffer solutions are used in except?
10. Consider the reaction PCl₅ (g) ⇌ PCl₃(g) +Cl₂ in a closed container at equilibrium. At a fixed temperature, what will be the effect of adding more PCl₅ on the equilibrium constant?
11. For which system does the equilibrium constant, Kc has units of (concentration)^-1:
12. For N₂ + 3H₂ ⇌ 2NH₃
13. For the reaction H₂(g) + I₂(g) ⇌ 2HI(g). The equilibrium constant changes with:
14. For what value of Kc almost forward reaction is complete?
15. If [Salt] = [Acid] then pH of an acidic buffer will be:
16. If the concentration of salt is greater than the acid in buffer solution, then the?
17. If the ionic product is equal to Ksp then the solution is:
18. If the temperature is increased of the following reaction, then will go in N₂ + 3H₂ ⇌ 2NH₃ ∆H = -Ve
19. In a given system, water and ice are in equilibrium, if the pressure is applied to the above system then:
20. In a saturated solution of AgCl, the molar concentration of Ag⁺ and Cl⁻ is 1.0 x 10⁻⁵ M each. What is the value of Ksp?
21. In the reaction a₂(g) + 4B₂(g) ⇌ 2AB4(g) such that ΔH < 0;the formation of AB4(g)will be favoured at:
22. In which of the following Equilibria will Kc and Kp have not the same value?
23. Its Ksp would be:
24. Ka value for acetic acid CH₃COOH at 25°C is:
25. pH of a buffer solution having 0.01M CH₃COONa and 0.1M CH₃COOH (pKa = 4.74) is:
26. pH of human blood is:
27. Solubility of Ca(OH)₂ is exothermic, its solubility will increase:
28. Strength of an acid can be determined by:
29. Strength of an acid is directly related to the value of:
30. The decomposition of N₂O₄ to NO₂ is carried out at 280°C in chloroform. When equilibrium is reached, 0.2 moles of N₂O₄ and 0.02 mole of NO₂ are present in 1:1 ratio. The equilibrium constant for the reaction N₂O₄ →2NO₂ is______.
31. The Ksp has units of mol².dm⁻⁶ in:
32. The Ksp of AgCl is 2.0 x 10⁻¹⁰ mol².dm⁻⁶. The maximum concentration of Ag^+1 ions in the solution is:
33. The Kw of water at 25°C is given by:
34. The maximum concentration of Ag⁺ ions in the solution is:
35. The molarity of pure water is:
36. The most suitable temperature for preparing ammonia gas is:
37. The oxidation of SO₂ to SO₃ is an exothermic reaction. The yield of SO₃ will be maximum if:
38. The pH of 0.001 M NaOH solution is:
39. The pH of 10⁻³ mol.dm⁻³ of H₃BO₃ solution is:
40. The pH of 10⁻⁴ mole dm⁻³of HCl:
41. The pH of an aqueous solution is 3.0 at 25°C. The hydrogen ion concentration in the solution would be:
42. The pH of an ideal buffer is:
43. The pH of soft drink is:
44. The pOH of 10⁻³ mol. dm⁻³ of H₂SO₄ solution is:
45. The pOH value of 0.001 M HCI solution in water is:
46. The substance which increases the rate of reaction, but remains unchanged at the end of reaction is called:
47. The sum of [1-1] and [OW] in pure water is:
48. The sum of PKa and PKb is:
49. The suppression of ionization of weak electrolyte in the presence of strong electrolyte with one same ion is called:
50. The unit of ""Kr"" for the reaction
51. The value of PKw at 25°C is:
52. Unit of Kw are:
53. What will be the pH of 1.0 mol dm⁻³ of NH₄OH, which is 1% dissociated?
54. When HCl gas is passed through the saturated solution of rock salt, the solubility of NaCl:
55. Which of the following can affect the Kc value of a reaction:
56. Which of the following efforts will change Ku for the reaction:
57. Which of the following will form a stable acidic buffer:
58. Which one increases by common ion effect except?
59. Which one is the best buffer those have:
60. Which one is very weak acid?
Short Questions
1. A mixture of NH₄OH and NH₄Cl give n=basic buffer. Justify?
2. By adjusting the ratio of salt and acid, we can adjust the pH of required buffer solution. How?
3. By diluting the solution of CH₃COOH, the % age ionization changes, but the dissociation constant of the acid remains the same at a constant temperature. How?
4. Calculate the pH of 10⁻⁴ mol dm⁻³ of Ba(OH)₂?
5. Calculate the pH of 10⁻⁴ moles dm⁻³ solution of HCl?
6. Define the effect of common ion on solubility? Give examples.
7. Give application of solubility product?
8. Give units of Kc for NH₃ synthesis?
9. How does a buffer act? Give example if acidic buffer?
10. How does a catalyst affect a reversible reaction?
11. How does the equilibrium constant of a chemical reaction tells us the direction of a chemical reaction?
12. How NaCl can be purified by common in effect?
13. Justify that chemical equilibrium is dynamic in nature?
14. Solid ice at 00C can be melted by applying pressure without supply of heat from outside. Why?
15. The change of temperature disturbs the equilibrium position and the equilibrium constant of reaction. Justify?
16. The change of volume of pressure disturbs the equilibrium position for some of the gaseous phase’s reactions but not the equilibrium constant. Why?
17. The NH₃ synthesis by Heber’s process is an exothermic reaction. It should be favored at low temperature, but the optimum temperature is 4000C. Why?
18. The rates of chemical reaction depends upon the concentration of reactants. Why?
19. Those gaseous reactions which happen with the increase of volume go to the backward direction, when the volume is decreased. Why?
20. What are solubility product expressions of PbCl₂, Ag₂CrO₄, AnXm?
21. What happens to the directions of a reversible reaction, when the ratio of the concentration is less than actual Kc?
22. What is a solution?
23. What is buffer capacity?
24. What is Henderson equation?
25. What is the concentration of hydroxide ion in a solution whose pH is 10?
26. What is the effect of rise in temperature on the solubility of Kl in water?
27. What is the meant by stage of chemical equilibrium?
28. What will be effect of change in pressure on NH₃ and SO₃ synthesis.
29. When four types of chemical equilibrium constants for a reaction become equal? How Kp and Kc are related?
30. When the concentration of the salt is increased in an acidic buffer, then the pH of the solution increases. Why?
31. Why are exothermoic reactions favoured to the forward direction by cooling, but reverse is true for endothermic reactions?
32. Why do we need buffer solution?
33. Why HCl acts as a weak acid in ethanoic acid as compared to, when dissolved in water?
34. Why HCl is added before passing H₂S gas in second group basic radical analysis?
35. Why is the equilibrium established, only when the reaction vessel is closed for a gaseous reaction?
36. Why the equilibrium constant value has its units for some of the reversible reactions, bur has no unit for some other reactions?
37. Why the factor of volume cancelled out in the final expression of Kc, when the number of moles of reactants and products are equal?
38. Why the factor volume in Kc expression goes to the denominator, when the number of moles of products is greater than the reactants for a reversible reaction?
39. Why the ionic product of water (Kw) increases with the increase of temperature?
40. Why the solubility of gaseous in water is increased by increasing the temperature?
41. Why the strong acids have weak conjugate bases, and weak acids have strong conjugate bases?
42. Why the sum of pH and pOH of any aqueous solution is always equal to 14, i.e. pkw at 25 ⁰C?
Long Questions
1. Derive Handerson's equation for acidic buffer.
2. What is Le-Chatelier's principle? Discuss effect of concentration on an equilibrium system.
3. How does a buffer work?
4. Discuss optimum conditions required for the synthesis of SO₂.
5. Differentiate between reversible and irreversible processes.
6. Q5. (a) How does Ke help to predict the direction of reaction?
7. What is law of mass action. Derive an equation for Kc expression of a general reversible reaction.
8. Benzoic acid C₆H₅COOH is a weak mono-basic acid (Ka-6.4 x 10⁻⁵ mol/dm³). What is the pH of a solution containing 7.2 g of sodium benzoate in one dm³ of 0.02 mol/dm benzoic acid.
9. What is the percentage ionization of acetic acid in a solution in which 0.1 moles of it has been dissolved per dm³ of the solution, Ka = 1.85 x 10⁻⁵.
10. What is buffer action?
11. Explain common ion effect with two examples.
12. The solubility of CaF₂ in water at 25°C is found to be 2.05 x 10⁴ mol/dm³. what is value of Ksp at this temperature.
13. What are the effects of changing temperature pressure and concentration on the following gaseous reactions?
14. Define pH and pOH. How are they related with pKw .
15. Write a note on synthesis of ammonia gas by Haber's process.