All questions of Chemical Equilibrium for EmSAT Achieve Exam

Ca(HCO₃)₂ is strongly heated and after equilibrium is attained, temperature changed to 25° C.

K_p = 36 (pressure taken in atm)
Thus, pressure set up due to CO₂ is

• a)
  36 atm
• b)
  18 atm
• c)
  12 atm
• d)
  6 atm

• a)
  Equilibrium
• b)
  Mass action
• c)
  Constant proportion
• d)
  Reciprocal proportions

• a)
  9.4
• b)
  8.0
• c)
  6.0
• d)
  9.0

Consider the following equilibrium in a closed container

At a fixed temperature, the volume of a reaction container is halved. For this change, which of the following statements holds true regarding the equilibrium constant (K_p) and degree of dissociation (α) ?

• a)
  Neither K_p nor α change
• b)
  Both K_p and α change
• c)
  K_p changes but α does not change
• d)
  K_p does not change but α changes

Following equilibrium is set up at 298 K in a 1 L flask.

If one starts with 2 moles of A and 1 mole of B, it is found that moles of B and D are equal.Thus K_c is 

• a)
  9.0
• b)
  15.0
• c)
  3.0
• d)
  0.0667

• a)
  Equilibrium is possible only in a closed system at a given temperature.
• b)
  All measurable properties of the system remain constant.
• c)
  All the physical processes stop at equilibrium.
• d)
  The opposing processes occur at the same rate and there is dynamic but stable condition.

Ag⁺(aq)+NH₃(aq) [Ag(NH₃)(aq)]⁺ ; K, = 3.5x 10^-3
[Ag(NH₃)]⁺ (aq)+NH₃(aq) [Ag(NH₃)₂]²⁺(aq); K₂ = 1.7x 10^-3
Formation constant of [Ag(NH₃)₂]⁺(aq) is

• a)
  2.06
• b)
  5.2 x 10^-3
• c)
  5.95 x 10^-6
• d)
  None of these

Graphite is added to a vessel that contains CO₂(g) at a pressure of 0.830 atm at a certain high temperature. The pressure rises due to a reaction that produces CO (g). The total pressure reaches an equilibrium value of 1.366 atm. Calculate the equilibrium constant of the following reaction.

• a)
  2.909 atm
• b)
  6.909 atm
• c)
  4.909 atm
• d)
  3.909 atm

• a)
  Reversible reaction
• b)
  Cyclic reaction
• c)
  Decomposition reaction
• d)
  Irreversible reaction

Direction (Q. Nos. 1-10) This section contains 10 multiple choice questions. Each question has four
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.

Q. Vapour pressure of NH₄HS (s)is 20 mm at 25°C, for

Total pressure when NH₄HS (s) dissociates at 25°Cin a vessel which already contains H₂S (g)at a pressure of 15 mm, is

• a)
  25 mm
• b)
  50 mm
• c)
  5 mm
• d)
  10 mm

Following equilibrium is set up at 1000 K and 1 bar in a 5 L flask,

At equilibrium, NO₂ is 50% o f the total volume. Thus, equilibrium constant K_c is 

• a)
  0.133
• b)
  0.266
• c)
  0.200
• d)
  0.400

Q. What is [PCI₅] eq?

• a)
  4.09 x 10^-4 mol L^-1
• b)
  2.444 x 10³ mol L^-1 
• c)
  4.09 x 10^-6 mol L^-1
• d)
  2.444 x 10⁵ mol L^-1

Passage II

The complex ion of Fe²⁺ with the chelating agent dipyridyl (abbreviated dipy) has been studied kinetically in both the forward and backward directions. For the complexion reaction,

the rate of the formation of the complex at 298 K is given by rate = (1. 45 x 10¹³ L³mol ^-3s^-1) [Fe ²⁺] [dipy]³ and for the reverse reaction , the rate of disapperance of the complex is

Q. What is equilibrium constant for the equilibrium ? 

• a)
  8.4138x 10^-18
• b)
  2.3770x 10¹⁷
• c)
  1.1885x 10¹⁷
• d)
  5.9426x 10⁶

Assume following equilibria when total pressure set up in each are equal to 1 atm, and equilibrium constant (K_p) as K₁; K₂ and K₃


Thus,

• a)
   K₁ = K₂ = K₃
• b)
  K₁ < K₂ < K₃
• c)
  K₃ < K₂ < K₁
• d)
  None of these

• a)
   0.20 bar
• b)
   0.017 ba
• c)
  0.040 bar
• d)
  0.10 bar

H₂O (l) H₂O(s) ; ΔH = -q

Application of pressure on this equilibrium

• a)
  cause formation of more ice
• b)
  cause fusion of ice
• c)
  has no effect
• d)
  lower the melting point

The equilibrium constant for the following reaction, is 1.6 x 10⁵ at 1024 K.

HBr (g)at 10.0 bar is introduced into a sealed container at 1024 K. Thus, partial pressure of H₂(g)and Br₂(g), together is

• a)
  10 bar
• b)
  0.05 bar
• c)
  0.025 bar
• d)
  0.10 bar

• a)
  s = [K_sp/27]^1/5
• b)
  s = K_sp^1/5
• c)
  s = K_sp^1/2
• d)
  s = [K_sp/108]^1/5

• a)
  10^-7
• b)
  10^-8
• c)
  10^-9
• d)
  10^-5

For the following electrochemical cell reaction at 298 K,
 
E^°cell = 1.10 V

• a)
  0.027
• b)
  37.22
• c)
  0.012
• d)
  85.73

• a)
  Cannot be predicted
• b)
  6.3 10^-3 M
• c)
  10^-6 M
• d)
  10^-3 M

For the reversible reaction, 

In a reaction vessel, [NO]= [O₂]= 0.01 mol L^-1 and [NO₂]= 0.1 mol L^-1 then above reaction is 

• a)
  shifted in forward direction
• b)
  shifted in backward direction
• c)
  in equilibrium
• d)
  not predictable in the absence of required data

A sample of N₂O₄(g)with a pressure of 1.00 atm is placed in a flask. When equilibrium is reached, 20% of N₂O₄(g)has been converted to NO₂(g)

If the original pressure is made 10% of the earlier pressure, then per cent dissociation will be

• a)
  20%
• b)
  42%
• c)
  54%
• d)
  62%

• a)
  20 percent
• b)
  33 percent
• c)
  100 percent
• d)
  98 percent

In the following equilibrium  AB  A⁺ + B^-
AB is 10% dissociated, when [AB] = 1M

Q. What is per cent dissociation if 1 M AB is dissociated in the presence of 1 M A⁺? 

• a)
  5.2%
• b)
  6.0%
• c)
  1.1%
• d)
  10.0%

Kc forthe decomposition of NH₄HS(s) is 1.8x 10^-4 at 25°C.

If the system already contains [NH₃] = 0.020 M, then when equilibrium is reached, molar concentration are

• a)
  a
• b)
  b
• c)
  c
• d)
  d

• a)
  0.0174
• b)
  0.174
• c)
  0.0348
• d)
  1.74

 is a gaseous phase equilibrium reaction taking place at 400 K in a 5 L flask. For this 

• a)
  K_c = K_p
• b)
  K_c = 25Kp
• c)
  K_p = 25K_c
• d)
  K_c = 5K_p 

For the following gaseous phase equilibrium,

K_p is found to be equal to K_x (K_x is equilibrium constant when concentration are taken in terms of mole fraction. This is attained when pressure is 

• a)
  1 atm
• b)
  0.5 atm
• c)
  2 atm
• d)
  4 atm

Variation of log K_p with temperature. 1/T is given by for the equilibrium.
NH₄HS (s)   NH₃(g) + H₂S

Q. The equilibrium is displaced in forward side on

• a)
  increasing temperature and decreasing pressure
• b)
  increasing temperature and pressure both
• c)
  decreasing temperature and pressure both
• d)
  decreasing temperature and increasing pressure

Passage I

Solid ammonium chloride is in equilibrium with ammonia and hydrogen chloride gases

0.980 g of solid NH₄CI is taken in a closed vessel of 1 L capacity and heated to 275° C.

Q. Percentage decomposition of the original sample is

• a)
  24.81%
• b)
  6.24%
• c)
  3.12%
• d)
  12.13%

• a)
  0.1 mol dm^–3 AgNO₃ solution
• b)
  0.1 mol dm^–3 HCl solution
• c)
  H₂O
• d)
  Aqueous ammonia​

Consider the following solubility data for various chromates at 25°C.

    Salt                                                K_sp

the chromate that is most suitable is?

• a)
  Ag₂CrO₄
• b)
  BaCrO₄
• c)
  PbCrO₄
• d)
  none of these

• a)
  [H3O+] = [OH-]
• b)
  [HA] = [K+]
• c)
  [HA] = [OH-]
• d)
  [H3O+] = [A-]

Which of the following on the addition will cause deep red colour to disappear?

• a)
  AgNO₃
• b)
  HgCI₂
• c)
  H₂C₂O₄
• d)
  H₂O

For the equilibrium,

at 1000 K. If at equilibrium p_CO = 10 then total pressure at equilibrium is 

• a)
  6.30 atm
• b)
  0.63 atm
• c)
  6.93 atm
• d)
  69.3 atm

• a)
  all types of system
• b)
  closed system
• c)
  open system
• d)
  isolated system

• A:

  ammonia

• B:

  sulfuric acid

• C:

  lactic acid

• D:

  both A and B

The answer is d.

Direction (Q. Nos. 21) Choice the correct combination of elements and column I and coloumn II  are given as option (a), (b), (c) and (d), out of which ONE option is correct.

The progress of the reaction  with time t is shown below.


Match the parameters in Column l with their respective values in Column II.


Codes

      

• a)
  a
• b)
  b
• c)
  c
• d)
  d

Direction (Q. Nos. 1-8) This section contains 8 multiple choice questions. Each question has four
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.

Q. For the following equilibrium,

Vapour density is found to be 100 when 1 mole of PCI₅ is taken in 10 dm³ flask at 300 K. Thus, equilibrium pressure is

• a)
  1.00 atm
• b)
  4.92 atm
• c)
  2.46 atm
• d)
  2.57 atm

Select the correct statement (s) about the following equilibrium.

• a)
  At constant vapour pressure, number of molecules leaving the liquid equals the number returning to liquid from vapour
• b)
  This does not represent the static equilibrium
• c)
  This represents dynamic equilibrium and the rate of the forward and backward reactions become equal
• d)
  This represents dynamic as well as static equilibrium

At 700 K and 350 bar, a 1 : 3 mixture of N₂(g) and H₂(g) reacts to form an equilibrium mixture containing X (NH₃)= 0.50. Assuming ideal behaviour K_p for the equilibrium reaction, 

• a)
  2.03x 10^-4
• b)
  3.55x 10^-3
• c)
  1.02 x 10^-4
• d)
  3.1 x 10^-4

Consider the following equilibrium,

N₂(g) + 3H₂(g) 2NH₃(g)

If N₂(g) is added to the above mixture in equilibrium,

[IIT JEE 2006]

• a)
  the equilibrium will shift to forward direction as entropy increases in the direction of spontaneous reaction
• b)
  the equilibrium constant K_p increases
• c)
  partial pressure of NH₃ as well as that of N₂ increases when equilibrium is reached
• d)
  the equilibrium constant K_p remains constant

• a)
  x²y²
• b)
  xy³
• c)
  x²y
• d)
  xy²

• a)
  to provide basic medium
• b)
  to provide acidic medium
• c)
  to increase the degree of dissociation of NH₄OH
• d)
  to suppress the degree of dissociation of NH₄OH

• a)
  Strong bases in the blood donot let pH change
• b)
  Stomach wall is resistant
• c)
  There are buffers in the blood which resist pH change
• d)
  Strong acids in the blood donot let pH change