Chemistry Chapter 6 Entry Test MCQs
26. For a reversible reaction 2HI ⇌ H2 + I2, by increasing pressure, the direction of reaction will be:
a. Unchanged
b. Forward
c. Change with time
d. Backward
27. The value of KC at 250C is 3.2 x 10-4 for the following reaction NO2 + CO ⇌ CO2 + NO, what would be the value of Kp for this reaction at same temperature.
a. 1.2 x 10-4
b. 6.4 x 10-4
c. 5.6 x 10-4
d. 3.2 x 10-4
28. For the reaction: 2A + B ⇌ 3C + D When equal moles of reactants are used,
which of the following must always be true when the system attained equilibrium?
a. [A] > [B]
b. [A] = [B]
c. [C] = [B]
d. [A] < [B]
29. Which one of the following statements does not describe the equilibrium state?
a. The concentration of the reactants is equal to the concentration of the products.
b. The rate of forward reaction is equal to the rate of the reverse reaction.
c. The concentration of the reactants and products reach a constant level.
d. Equilibrium is dynamic and there is no net conversion to reactants and products.
30. Which statement is true about equilibrium constant?
a. changes as product concentration changes
b. remains same
c. changes as temperature changes.
d. changes as reactant concentration changes
31. The equilibrium equation for the forward reaction: 2CH4 (g) + 3O2 (g) ⇌ 2CO (g) + 4H2O (g)
a. KC = 2[CH4]+ [O2]/2[CO]+4 [H2O]
b. KC = [CH4]2 +[O2]3/ [CO]2 +[H2O]4
c. KC = 2[CO]+ 4 [H2O]/2[CH4]+ 3 [O2]
d. KC = [CO]2[H2O]4/[CH4]2[O2]3
32. Nitric oxide reacts with oxygen to form nitrogen dioxide:2NO (g) + O2 (g) ⇌2NO2 (g) What is Kc ‘ for the reverse reaction if the equilibrium concentration of NO is 0.300 M, O2 is 0.200 M, and NO2 is 0.30 M at 25oC?
a. 5.00
b. 0.1584
c. 1.641
d. 6.24
33. If Kc is the equilibrium constant for a forward reaction what is Kc for the reverse reaction?
a. Kc
b. 1/Kc
c. – Kc
d. None
34. Which one of the following statements about the equilibrium constant (Kp) is false?
a. Δn = the sum of the coefficients of gaseous products – the sum of the coefficients of gaseous reactants
b. The relationship is: Kp = Kc (RT)Δn
c. The units for Kp are usually used for solids
d. Total pressures are used in the equilibrium equation in place of molar concentrations.
35. What is the value of Kc for reaction N2O4 ⇌ 2NO2 if at equilibrium the concentration of N2O4 is 4 × 10-2 mole/dm3 and that of NO2 is 2 × 10-2 mole/dm3
a. 2 × 10-2
b. 1 × 10-2
c. 8 × 10-2
d. 4 × 10-2
36. The equilibrium expression for reaction is KC = 4x2V/(𝐚−𝟐𝐱)𝟐(𝐛−𝐱)
a. Increase of pressure shifts equilibria to right
b. Increase of pressure increases Kc
c. Increase of pressure decreases Kc
d. Both “A” and “B”
37. The equilibrium expression for a reaction is Kc = x2/V(a – x), what is true for this reaction.
a. Decrease of pressure favours forward reaction
b. Increase of pressure favours forward reaction
c. Decrease of pressure favours backward reaction
d. Increase of volume favours backward reaction
38. In a reaction A + B ⇌ C + D. If the initial amounts of both reactants are 1 mole each, and at equilibrium 0.75 mole of C were found. What is the Kc of this reaction?
a. 6
b. 4
c. 9
d. 8
39. The initial concentration of the reactants is ‘a’ mole and ‘x’ mole is the equilibrium concentration of the product. The equilibrium expression of reaction will be 2NO2(s) ⇌ N2O4(g)
a. 2x2V/(a-2x)2
b. 4x2/(a-x)V
c. x.V/(a-2x)2
d. 2x2V/(a-2x)2
40. One mole of N2, two moles of NH3 and three moles of H2 are present at equilibrium in a container of volume 1dm3. The value of Kc will be
a. 4/27
b. 27/2
c. 4
d. 2/27
41. Which Kc value indicates that the chemical reaction reaches easiest to completion?
a. 105
b. 10-3
c. 103
d. 1010
42. Which is the correct relationship?
a. Kc = Kp(RT)Δn
b. Kp = Kc(RT)Δn
c. Kp = Kc(RT)n
d. Kp = Kc(P)Δn
43. Kc = 𝒙𝟐/𝒗(𝒂−𝒙) this equation holds true for
a. H2 + I2⇌ 2HI
b. 2NO ⇌ N2O4
c. CH3COOH + C2H5OH ⇌ CH3COOC2H5 + H2O
d. PCl5⇌ PCl3 + Cl2
44. The reaction rate in forward direction decreases with the passage of time because:
a. Concentration of reactants decreases
b. Concentration of product increases
c. Temperature of the system changes
d. The order of reaction changes
45. A reversible reaction:
a. Spontaneous reaction
b. Never goes to completion
c. Non-spontaneous reaction
d. Always completes
46. For which system does the equilibrium constant, Kc has units of (concentration)-1?
a. 2NO ⇌ N2O4
b. N2 + 3H2⇌ 2NH3
c. 2HI ⇌ H2 + I2
d. 2HF ⇌ H2 + F2
47. At equilibrium:
a. All chemical reactions have ceased
b. The rates of the forward and reverse reactions are equal
c. The value of the equilibrium constant is 1
d. The rate constants of the forward and reverse reactions are equal
48. Which of the following factors can affect the position of equilibrium in a reversible reaction?
a. Pressure
b. Temperature
c. Concentration of reactants
d. All of the above
49. Which of the following is an example of a reversible reaction?
a. Formation of water from hydrogen and oxygen at 1500oC
b. Digestion of food in the stomach
c. Reaction of sodium with water
d. Combustion of gasoline in a car engine
50. The equilibrium constant (Kc) for the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) is 0.05. What does this value indicate about the reaction?
a. The reaction favours the products
b. The reaction favours the reactants
c. The reaction is not possible.
d. The reaction is at equilibrium