JEE Questions for Chemistry Equilibrium Quiz 5 - MCQExams.com

5 mL of 0.4 N NaOH is mixed with 20 mL of 0.1 N HCl. The pH of the resulting solution will be
  • 7
  • 8
  • 5
  • 6
The pH of the solution obtained by mixing 100 mL of a solution of pH = 3 with 400 mL of a solution of pH = 4, is
  • 7 - log 2.8
  • 4 - log 2.8
  • 5 - log 2.8
  • 3 - log 2.8
A solution [H3 O+ ] is 10-4. The solution is
  • acidic
  • basic
  • neutral
  • amphoteric
P4 (s) + 5O2(g) ⇌ P4010 (s) What is the equilibrium expression for the above reaction ?

  • Chemistry-Equilibrium-3536.png
  • 2)
    Chemistry-Equilibrium-3537.png

  • Chemistry-Equilibrium-3538.png

  • Chemistry-Equilibrium-3539.png
Consider the reactions
NO2 ⇌ 1/2 N2 + O2, K1 and N2O4 ⇌ 2NO2, K2
Give the equilibrium constant for the formation of N2O4 from N2 and O2.

  • Chemistry-Equilibrium-3540.png
  • 2)
    Chemistry-Equilibrium-3541.png

  • Chemistry-Equilibrium-3542.png

  • Chemistry-Equilibrium-3543.png
The equilibrium constant for the reaction
SO2 (g) + 1/2 O2 (g) ⇌ SO3(g) is 5 × 10-2 atm. The equilibrium constant of the equation
2SO3 (g) ⇌ 2SO2 (g) + O2 (g) would be
  • 100 atm
  • 200 atm
  • 4 × 102 atm
  • 6.25 × 104 atm
By applying law of mass action, the equilibrium constant K for the reaction
HA + H2O ⇌ H3O+ + A-, is given as

  • Chemistry-Equilibrium-3545.png
  • 2)
    Chemistry-Equilibrium-3546.png

  • Chemistry-Equilibrium-3547.png

  • Chemistry-Equilibrium-3548.png
For the reaction H2 + I2 ⇌ 2 HI, the equilibrium concentration of H2, I2 and HI are 8.0, 3.0 and 28.0 mol/L, respectively. The equilibrium constant is
  • 28.34
  • 32.66
  • 34.78
  • 38.88
Ag+ + NH3 ⇌ [Ag (NH3)]+, K1 = 3.5 × 10-3 [Ag(NH3)]+ + NH3 ⇌ [Ag (NH3)2]+, K2 = 1.7 × 10-3
Then the formation constant of [Ag (NH3)2]+ is
  • 6.08 × 10-6
  • 6.08 × 106
  • 6.08 × 10-9
  • None of these
Phosphorus pentacloride dissociates as follows, in a closed reaction vessel,
PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)
If total pressure at equilibrium of the reaction mixture is P and degree of dissociation of PCl5 is x, then the partial pressure of PCl3 will be

  • Chemistry-Equilibrium-3549.png
  • 2)
    Chemistry-Equilibrium-3550.png

  • Chemistry-Equilibrium-3551.png

  • Chemistry-Equilibrium-3552.png
SO3 (g) ⇌ SO2 (g) + 1/2 O2 (g)
The equilibrium constant for the above reaction is KC = 4.9 × 10-2. The value of KC for the reaction
2SO2 (g) + O2 (g) ⇌ 2SO3 (g) will be
  • 416
  • 2.40 × 10-3
  • 9.8 × 10-2
  • 4.9 × 10-2
1 mole of N2O4 (g) at 300 K is kept in closed container under 1 atm. It is heated to 600 K when 20% by mass of N2O4 (g) decomposes to NO2 (g). The resultant pressure is
  • 1.2 atm
  • 2.4 atm
  • 2.0 atm
  • 1.0 atm
N2 + O2 ⇌ 2NO + Heat
In the above gaseous reversible reaction, if pressure is increased, then the equilibrium constant would be
  • unchanged
  • increased
  • decreased
  • sometimes increased, sometimes decreased
Consider the following equilibrium in a closed container,
N2O4 (g) ⇌ 2 NO2 (g)
At a fixed temperature, the volume of the reaction container is halved. For this change, which of the following statement holds true regrading the equilibrium constant (KP) and degree of dissociation (α) ?
  • Neither KP nor α changes
  • Both KP nor α changes
  • KP changes but α does not
  • KP does not change but α changes
The equilibrium constant of a reaction is 300. If the volume of reaction flask is tripled, then the equilibrium constant is
  • 300
  • 600
  • 900
  • 100
In the reaction H2 + I2 ⇌ 2HI
In a 2 L flask, 0.4 mole of each H2 and I2 are taken. At equilibrium, 0.5 moles of HI are formed. What will be the value of equilibrium constant KC?
  • 20.2
  • 25.4
  • 0.284
  • 11.11
Two moles of PCl5 were heated in a closed vessel of 2 L. At equilibrium, 40% of PCl5 is dissociated into PCl3 and Cl2. The value of equilibrium constant is
  • 0.53
  • 0.267
  • 2.63
  • 5.3
56 g of nitrogen and 8 g of hydrogen gas are heated in a closed vessel. At equilibrium, 34 g of ammonia are present. The equilibrium number of moles of nitrogen, hydrogen and ammonia respectively are
  • 1, 2, 2
  • 2, 2, 1
  • 1, 1, 2
  • 2, 1, 2
Which of the following is not a characteristic property of chemical equilibrium ?
  • Rate of forward reaction is equal to rate of backward reaction at equilibrium
  • After reaching the chemical equilibrium, the concentrations of reactants and products remain unchanged with time
  • For A (g) ⇌ B (g), KC is 10-2. If this reaction is carried out in the presence of catalyst, the value of KC decreases
  • After reaching the equilibrium, both forward and backward reactions continue to take place
A monoprotic weak acid (HA) is ionised 5% in 0.1 M aqueous solution. What is the equilibrium constant for its ionisation ?
HA (a) + H2O (l) ⇌ H3O+ (aq) + A- (aq)
  • 2.63 × 104
  • 2.63 × 103
  • 2.63 × 10-4
  • 2.63 × 10-3
The equilibrium reaction that is not influenced by volume change at constant temperature is
  • H2 (g) + I2 (g) ⇌ 2HI (g)
  • N2 (g) + 3H2 (g) ⇌ 2 NH3 (g)
  • N2O4 (g) ⇌ 2NO2 (g)
  • 2NO (g) + O2 (g) ⇌ 2NO2 (g)
Which one of the following substances has the highest proton affinity ?
  • H2O
  • H2S
  • NH3
  • PH3
Which of the following is not a conjugate acid-base pair?
  • HPO32-, PO33-
  • H2PO4-, HPO42-
  • H3PO4. H2PO4-
  • H2PO4-, PO33-
At a given temperature, the equilibrium constant for the reaction of
PCl5 ⇌ PCl3 + Cl2 is 2.4 × 10-3. At the same temperature, the equilibrium constant for the reaction
PCl3 (g) + Cl2 ⇌ PCl5 (g) is
  • 2.4 × 10-3
  • -2.4 × 10-3
  • 4.2 × 102
  • 4.8 × 10-2
Which of the following is correct for the reaction ?
N2 (g) + 3H2 (g) ⇌ 2 NH3 (g)
  • KP = KC
  • KP < KC
  • KP > KC
  • pressure is required to predict the correlation
For the reaction,
2NO2 (g) ⇌ 2NO (g) + O2 (g)
(KC = 1.8 × 10-6 at 184o C)
(R = 0.00831 KJ/mol K)
where KP and KC are compared at 184o C, it is found that
  • whether KP is greater than,less than or equal to KC depends upon the total gas pressure
  • KP = KC
  • KP is less than KC
  • KP is greater than KC
An amount of solid NH4HS is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm pressure. Ammonium hydrogen sulphide decomposes to yield NH3 and H2S gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to 0.84 atm. The equilibrium constant for NH4HS decomposition at this temperature is
  • 0.11
  • 0.17
  • 0.18
  • 0.30
In which of the following reactions is KP < KC ?
  • I2 (g) ⇌ 2I (g)
  • 2BrCl (g) ⇌ Cl2 (g) + Br2 (g)
  • CO (g) + 3H2 (g) ⇌ CH4 (g) + H2O (g)
  • All the above
The change in pressure will not effect the equilibrium constant for
  • N2 + 3H2 ⇌ 2 NH3
  • PCl5 ⇌ PCl3 + Cl2
  • H2 + I2 ⇌ 2HI
  • All of the above
For a reaction H2 + I2 ⇌ 2HI at 721K, the value of equilibrium constant is 50. If 0.5 mole each of H2 and I2 is added to the system, then the value of equilibrium constant will be
  • 40
  • 60
  • 50
  • 30
If in the reaction N2O4 ⇌ 2 NO2, x is that part of N2O4 which dissociates, then the number of molecules at equilibrium will be
  • 1
  • 3
  • 1 + x
  • (1 + x)2
At 550 K, the value of KC for the following reaction is 104 mol-1 L
X (g) + Y (g) ⇌ Z (g)
At equilibrium, it was observed that
[X] = 1/2 [Y] = 1/2 [Z]
What is the value (in mol L-1) of [Z] at equilibrium ?
  • 2 × 10-4
  • 10-4
  • 2 × 104
  • 104
2Ag2 O (s) ⇌ 4 Ag (s) + O2 (g)
Partial pressure of O2 in the above reaction is
  • KP
  • √KP
  • 3√KP
  • 2KP
In the reaction at constant volume
C (s) + CO2 (g) ⇌ 2CO (g)
Argon gas is added which does not take part in the reaction, choose the correct statement.
  • The equilibrium constant is unchanged
  • The equilibrium shifts in the forward direction
  • The equilibrium shifts in the backward direction
  • The direction of equilibrium depends on the amount of argon added
The thermal dissociation of equilibrium of CaCO3 (S) is studied under different conditions.
CaCO3 (s) ⇌ CaO (s) + CO2 (g)
For this equilibrium, the correct statement (s) is (are)
  • ∆H is dependent on T
  • K is not independent of the initial amount of CaCO3
  • K is dependent on the pressure of CO2 at given T
  • ∆H is independent of the catalyst, if any
2SO2 + O2 ⇌ 2SO3 + Heat.
The equilibrium reaction given above proceeds in forward direction by
  • addition of O2
  • removal of O2
  • addition of inert gas
  • cannot proceed
The exothermic formation of ClF3 is represented by the equation
Cl2 (g) + 3F2 (g) ⇌ 2ClF3 (g); ∆H = -329 KJ
Which of the following will increase the quantity of ClF3 in an equilibrium mixture of Cl2 , F2 and ClF3?
  • Adding F2
  • Increasing the volume of the container
  • Removing Cl2
  • Increasing the temperature
If pressure increases then its effect on given equilibrium
2NO (g) ⇌ N2 (g) + O2 (g) is shift in
  • forward direction
  • backward direction
  • no effect
  • None of the above
In Lowry-Bronsted concept, H+ donor is known as
  • acid
  • base
  • Both (and (2)
  • None of these
What is the best description of the change that occurs when N2O (s) is dissolved in water?
  • Oxidation number of sodium decreases
  • Oxide ion accepts sharing in a pair of electrons
  • Oxide ion donates a pair of electrons
  • Oxidation number of oxygen increases
Three reaction involving H2PO4- are given below
I. H3PO4 → H3O+ + H2PO4-
II. H2PO4- + H2O → HPO2-4 + H3O+
III. H2PO-4 + OH- → H3PO4 + O2-
In which of the above does H2PO4- act as an acid ?
  • only II
  • Both I and II
  • only III
  • only I
At a certain temperature, the dissociation constants of formic acid and acetic acid are 1.8 × 10-4 and 1.8 × 10-5, respectively. The concentration of acetic acid solution in which the hydrogen ion has the same concentration as in 0.001M formic acid solution is equal to
  • 0.01M
  • 0.001M
  • 0.1M
  • 0.0001M
  • 0.1010M
Diacidic base is ?
  • CH2 (OH)2
  • Ca (OH)2
  • CH3CH(OH)2
  • All og these
Which of the following behaves as Lewis acid and not as Bronsted acid?
  • HCl
  • H2SO4
  • HSO3-
  • SO3
Water is well known amphoprotic solvent. In which chemical reaction, water is behaving as a base ?
  • H2SO4 + H2O → H3O+ + HSO4-
  • H2O + H2O → H3O+ + OH-
  • H2O + NH2- → NH3 + OH-
  • H2O + NH3 → NH4+ + OH-
Which of the following is the weakest acid ?
  • HCl
  • HF
  • H2SO4
  • HNO3
According to hard and soft acid-base principle, a hard acid
  • has low charge density
  • show preference for soft bases
  • show preference for donor atoms of low electronegativity
  • is not polarisable
Four species are listed below
I . HCO3-
II. H3O+
III. HS4-
IV. HSO3F
Which one of the following is the correct sequence of their acid strength ?
  • IV < II < III < I
  • II < III < I < IV
  • I < III < II < IV
  • III < I < IV < II
Which of the following is lewis acid ?
  • Cl-
  • H3O+
  • PF3
  • C2H5OH
Amines behave as
  • Lewis acid
  • Lewis base
  • aprotic acid
  • neutral compound
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