Practice Corner MCQs

Question 1 of 69

1. Question

A reversible reaction is one which :

Proceeds in one direction
Proceeds in both directions
Proceeds spontaneously
All the statements are wrong

Question 2 of 69

2. Question

The equilibrium constant \(K_c\) for the reaction

\(
\mathrm{P}_4(\mathrm{~g}) \rightleftharpoons 2 \mathrm{P}_2(\mathrm{~g})
\)
is 1.4 at \(400^{\circ} \mathrm{C}\). Suppose that 3 moles of \(\mathrm{P}_4(\mathrm{~g})\) and 2 moles of \(\mathrm{P}_2(\mathrm{~g})\) are mixed in 2 litre container at \(400^{\circ} \mathrm{C}\). What is the value of reaction quotient \(\left(Q_c\right)\) ?

\(\frac{3}{2}\)
[latex]\frac{2}{3}[/latex]
1
None of these

Question 3 of 69

3. Question

In a chemical reaction equilibrium is established when :

Opposing reaction ceases
Concentrations of reactants and product are equal
Velocity of opposing reaction is the same as that of forward reaction
Reaction ceases to generate heat

Question 4 of 69

4. Question

The equilibrium constant for a reaction is \(K\), and the reaction quotient is \(Q\). For a particular reaction mixture, the ratio \(\frac{K}{Q}\) is 0.33 . This means that :

the reaction mixture will equilibrate to form more reactant species
the reaction mixture will equilibrate to form more product species
the equilibrium ratio of reactant to product concentrations will be 3
the equilibrium ratio of reactant to product concentrations will be 0.33

Question 5 of 69

5. Question

Consider the reaction \(2 \mathrm{SO}_2(g)+\mathrm{O}_2(g) \rightleftharpoons 2 \mathrm{SO}_3(g)\) for which \(K_c=278 M^{-1} .0 .001\) mole of each of the reagents \(\mathrm{SO}_2(g), \mathrm{O}_2(g)\) and \(\mathrm{SO}_3(g)\) are mixed in a 1.0 L flask. Determine the reaction quotient of the system and the spontaneous direction of the system :

[latex]Q_c=1000[/latex]; the equilibrium shifts to the right
[latex]Q_c=1000[/latex]; the equilibrium shifts to the left
[latex]Q_c=0.001[/latex]; the equilibrium shifts to the left
[latex]Q_c=0.001[/latex]; the equilibrium shifts to the right

Question 6 of 69

6. Question

For the reaction \(A(g)+3 B(g) \rightleftharpoons 2 C(g)\) at \(27^{\circ} \mathrm{C}, 2\) moles of \(A, 4\) moles of \(B\) and 6 moles of \(C\) are present in 2 litre vessel. If \(K_c\) for the reaction is 1.2 , the reaction will proceed in :

forward direction
backward direction
neither direction
none of these

Question 7 of 69

7. Question

For a reversible gaseous reaction \(\mathrm{N}_2+3 \mathrm{H}_2 \rightleftharpoons 2 \mathrm{NH}_3\) at equilibrium, replaced by same number of moles of \(\mathrm{T}_2\) ( T is tritium, isotope of H and assume isotopes do \(\mathrm{n}_{\mathrm{Ot}}\) have different chemical properties) without affecting other parameters, then :

The sample of ammonia obtained after sometime will be radioactive.
Moles of [latex]\mathrm{N}_2[/latex] after the change will be different as compared to moles of [latex]\mathrm{N}_2[/latex] present before the change
The value of [latex]K_p[/latex] or [latex]K_c[/latex] will change
The average molecular mass of new equilibrium will be same as that of old equilibrium

Question 8 of 69

8. Question

Using molar concentrations, what is the unit of \(K_c\) for the reaction?

\(
\mathrm{CH}_3 \mathrm{OH}(\mathrm{~g}) \rightleftharpoons \mathrm{CO}(\mathrm{~g})+2 \mathrm{H}_2(\mathrm{~g})
\)

\(M^{-2}\)
[latex]M^2[/latex]
[latex]M^{-1}[/latex]
[latex]M[/latex]

Question 9 of 69

9. Question

What is the unit of \(K_p\) for the reaction?

\(
\mathrm{CS}_2(g)+4 \mathrm{H}_2(g) \rightleftharpoons \mathrm{CH}_4(g)+2 \mathrm{H}_2 \mathrm{~S}(g)
\)

atm
[latex]\mathrm{atm}^{-2}[/latex]
[latex]\mathrm{atm}^2[/latex]
[latex]\mathrm{atm}^{-1}[/latex]

Question 10 of 69

10. Question

What is the equilibrium expression for the reaction \(\mathrm{P}_4(s)+5 \mathrm{O}_2(g) \rightleftharpoons \mathrm{P}_4 \mathrm{O}_{10}(s)\)

\(K_c=\left[\mathrm{O}_2\right]^5\)
[latex]K_c=\left[P_4 \mathrm{O}_{10}\right] / 5\left[\mathrm{P}_4\right]\left[\mathrm{O}_2\right][/latex]
[latex]K_c=\left[\mathrm{P}_4 \mathrm{O}_{10}\right] /\left[\mathrm{P}_4\right]\left[\mathrm{O}_2\right]^5[/latex]
[latex]K_c=1 /\left[\mathrm{O}_2\right]^5[/latex]

Question 11 of 69

11. Question

At \(527^{\circ} \mathrm{C}\), the reaction given below has [/latex]K_c=4[/latex]

\(
\mathrm{NH}_3(g) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(g)+\frac{3}{2} \mathrm{H}_2(g)
\)

What is the \(K_p\) for the reaction?

\(
\mathrm{N}_2(g)+3 \mathrm{H}_2(g) \rightleftharpoons 2 \mathrm{NH}_3(g)
\)

\(16 \times(800 R)^2\)
[latex]\left(\frac{800 R}{4}\right)^{-2}[/latex]
[latex]\left(\frac{1}{4 \times 800 R}\right)^2[/latex]
None of these

Question 12 of 69

12. Question

The equilibrium constant for the reaction \(\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})\) at temperature (T) is \(4 \times 10^{-4}\). The value of \(K_c\) for the reaction \(\mathrm{NO}(g) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(g)+\frac{1}{2} \mathrm{O}_2(g)\) at the same temperature is :

\(4 \times 10^{-4}\)
50
[latex]2.5 \times 10^2[/latex]
0.02

Question 13 of 69

13. Question

The equilibrium constant \(K_c\) for the following reaction at \(842^{\circ} \mathrm{C}\) is \(7.90 \times 10^{-3}\). What is \(K_p\) at same temperature?

\(
\frac{1}{2} \mathrm{~F}_2(g) \rightleftharpoons \mathrm{F}(g)
\)

\(8.64 \times 10^{-5}\)
[latex]8.26 \times 10^{-4}[/latex]
[latex]7.90 \times 10^{-2}[/latex]
[latex]7.56 \times 10^{-2}[/latex]

Question 14 of 69

14. Question

The equilibrium constant \(K_p\) for the following reaction at \(191^{\circ} \mathrm{C}\) is 1.24 . What is \(K_c\) ?

\(
\mathrm{B}(s)+\frac{3}{2} \mathrm{~F}_2(g) \rightleftharpoons \mathrm{BF}_3(g)
\)

6.7
0.61
8.30
7.6

Question 15 of 69

15. Question

For the equilibrium \(\mathrm{SO}_2 \mathrm{Cl}_2(g) \rightleftharpoons \mathrm{SO}_2(g)+\mathrm{Cl}_2(g)\), what is the temperature at which \(\frac{K_p(\mathrm{~atm})}{K_c(\mathrm{M})}=3\) ?

0.027 K
0.36 K
36.54 K
273 K

Question 16 of 69

16. Question

at \(500^{\circ} \mathrm{C}\), the value of \(K_p\) is \(1.44 \times 10^{-5}\) when partial pressure is measured in atmospheres. The corresponding value of \(K_c\) with concentration in mole litre \({ }^{-1}\), is:

[latex]1.44 \times 10^{-5} /(0.082 \times 500)^{-2}[/latex]
[latex]1.44 \times 10^{-5} /(8.314 \times 773)^{-2}[/latex]
[latex]1.44 \times 10^{-5} /(0.082 \times 773)^2[/latex]
[latex]1.44 \times 10^{-5} /(0.082 \times 773)^{-2}[/latex]

Question 17 of 69

17. Question

For the reaction \(\mathrm{CO}(g)+\mathrm{Cl}_2(g) \rightleftharpoons \mathrm{COCl}_2(g)\) the value of \(\frac{K_c}{K_p}\) is equal to :

[latex]\sqrt{R T}[/latex]
[latex]R T[/latex]
[latex]\frac{1}{R T}[/latex]
1.0

Question 18 of 69

18. Question

The concentration of a pure solid or liquid phase is not included in the expression of equilibrium constant because :

density of solid and liquid are independent of their quantities.
solids and liquids react slowly.
solids and liquids at equilibrium do not interact with gaseous phase.
the molecules of solids and liquids cannot migrate to the gaseous phase.

Question 19 of 69

19. Question

A catalyst is a substance which :

increases the equilibrium concentration of the product.
changes the equilibrium constant of the reaction.
shortens the time to reach equilibrium.
supplies energy to the reaction.

Question 20 of 69

20. Question

What will be the effect on the equilibrium constant on increasing temperature, it the reacion neither absorbs heat nor releases heat ?

Equilibrium constant will remain constant.
Equilibrium constant will decrease.
Equilibrium constant will increase.
Can not be predicted.

Question 21 of 69

21. Question

The equilibrium constant for the reaction \(\mathrm{N}_2(g)+\mathrm{O}_2(g) \rightleftharpoons 2 \mathrm{NO}(g)\) is \(4 \times 10^{-4}\) at 200 K . In presence of a catalyst, equilibrium is attained ten times faster. Therefore, the equilibrium constant in presence of the catalyst at 200 K is :

[latex]40 \times 10^{-4}[/latex]
[latex]4 \times 10^{-4}[/latex]
[latex]4 \times 10^{-3}[/latex]
difficult to compute without more data

Question 22 of 69

22. Question

For the reaction \(\mathrm{H}_2(g)+\mathrm{I}_2(g) \rightleftharpoons 2 \mathrm{HI}(g)\), the equilibrium constant changes with :

total pressure
catalyst
concentration of [latex]\mathrm{H}_2[/latex] and [latex]\mathrm{I}_2[/latex]
temperature

Question 23 of 69

23. Question

Consider the reactions
(i) \(2 \mathrm{CO}(\mathrm{g})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \rightleftharpoons 2 \mathrm{CO}_2(\mathrm{~g})+2 \mathrm{H}_2(\mathrm{~g})\); Eqm. Constant \(=K_1\)
(ii) \(\mathrm{CH}_4(g)+\mathrm{H}_2 \mathrm{O}(g) \rightleftharpoons \mathrm{CO}(g)+3 \mathrm{H}_2(g)\); Eqm. Constant \(=K_2\)
(iii) \(\mathrm{CH}_4(g)+2 \mathrm{H}_2 \mathrm{O}(g) \rightleftharpoons \mathrm{CO}_2(g)+4 \mathrm{H}_2(g)\); Eqm. Constant \(=K_3\)

Which of the following relation is correct ?

[latex]K_3=\frac{K_1}{K_2}[/latex]
[latex]K_3=\frac{K_1^2}{K_2^2}[/latex]
[latex]K_3=K_1 K_2[/latex]
[latex]K_3=\sqrt{K_1} \cdot K_2[/latex]

Question 24 of 69

24. Question

An equilibrium mixture of the reaction \(2 \mathrm{H}_2 \mathrm{~S}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{H}_2(\mathrm{~g})+\mathrm{S}_2(\mathrm{~g})\) had 0.5 mole \(\mathrm{H}_2 \mathrm{~S}, 0.10\) mole \(\mathrm{H}_2\) and 0.4 mole \(\mathrm{S}_2\) in one litre vessel. The value of equilibrium constant \((\mathrm{K})\) in \(\mathrm{m}_{\mathrm{ol}}\) litre \({ }^{-1}\) is :

0.004
0.008
[latex]0.016^{\circ}[/latex]
0.160

Question 25 of 69

25. Question

Given \(\left[\mathrm{CS}_2\right]=0.120 M,\left[\mathrm{H}_2\right]=0.10,\left[\mathrm{H}_2 \mathrm{~S}\right]=0.20\) and \(\left[\mathrm{CH}_4\right]=8.40 \times 10^{-5} M\) for the following reaction at \(900^{\circ} \mathrm{C}\), at eq. Calculate the equilibrium constant \(\left(K_c\right)\).

\(
\mathrm{CS}_2(g)+4 \mathrm{H}_2(g) \rightleftharpoons \mathrm{CH}_4(g)+2 \mathrm{H}_2 \mathrm{~S}(g)
\)

0.0120
0.0980
0.280
0.120

Question 26 of 69

26. Question

The equilibrium constant for the following reaction is 10.5 at 500 K . A system at equilibrium has \([\mathrm{CO}]=0.250 \mathrm{M}\) and \(\left[\mathrm{H}_2\right]=0.120 \mathrm{M}\). What is the \(\left[\mathrm{CH}_3 \mathrm{OH}\right]\) ?

\(
\mathrm{CO}(g)+2 \mathrm{H}_2(g) \rightleftharpoons \mathrm{CH}_3 \mathrm{OH}(g)
\)

0.0378
0.0435
0.546
0.0499

Question 27 of 69

27. Question

When sulphur (in the form of \(\mathrm{S}_8\) ) is heated at temperature \(T\), at equilibrium, the pressure of \(\mathrm{S}_8\) falls by \(30 \%\) from 1.0 atm , because \(\mathrm{S}_8(g)\) is partially converted into \(\mathrm{S}_2(g)\).
Find the value of \(K_p\) for this reaction.

2.96
6.14
204.8
None of these

Question 28 of 69

28. Question

9.2 grams of \(\mathrm{N}_2 \mathrm{O}_4(g)\) is taken in a closed one litre vessel and heated till the following equilibrium is reached \(\mathrm{N}_2 \mathrm{O}_4(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}_2(\mathrm{~g})\)
At equilibrium, \(50 \% \mathrm{~N}_2 \mathrm{O}_4(\mathrm{~g})\) is dissociated. What is the equilibrium constant (in mol litre \({ }^{-1}\) ) (molecular weight of \(\mathrm{N}_2 \mathrm{O}_4=92\) )

0.1
0.4
0.2
2

Question 29 of 69

29. Question

Two moles of \(\mathrm{NH}_3\) when put into a previously evacuated vessel (one litre), partially dissociated into \(\mathrm{N}_2\) and \(\mathrm{H}_2\). If at equilibrium one mole of \(\mathrm{NH}_3\) is present, the equilibrium constant is :

\(3 / 4 \mathrm{~mol}^2\) litre \({ }^{-2}\)
[latex]27 / 64 \mathrm{~mol}^2[/latex] litre [latex]{ }^{-2}[/latex]
[latex]27 / 32 \mathrm{~mol}^2[/latex] litre [latex]^{-2}[/latex]
[latex]27 / 16 \mathrm{~mol}^2[/latex] litre [latex]^{-2}[/latex]

Question 30 of 69

30. Question

\(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}(s) \rightleftharpoons \mathrm{CuSO}_4 \cdot 3 \mathrm{H}_2 \mathrm{O}(s)+2 \mathrm{H}_2 \mathrm{O}(g) ; K_p=4 \times 10^{-4} \mathrm{~atm}^2\). If the vapour pressure of water is 38 torr then percentage of relative humidity is : (Assume all data at constant temperature)

4
10
40
None of these

Question 31 of 69

31. Question

In the presence of excess of anhydrous \(\mathrm{SrCl}_2\), the amount of water taken up is governed by \(K_p=10^{12} \mathrm{~atm}^{-4}\) for the following reaction at 273 K

\(
\mathrm{SrCl}_2 \cdot 2 \mathrm{H}_2 \mathrm{O}(\mathrm{~s})+4 \mathrm{H}_2 \mathrm{O}(\mathrm{~g}) \rightleftharpoons \mathrm{SrCl}_2 \cdot 6 \mathrm{H}_2 \mathrm{O}(\mathrm{~s})
\)

What is equilibrium vapour pressure (in torr) of water in a closed vessel that contains \(\mathrm{SrCl}_2 \cdot 2 \mathrm{H}_2 \mathrm{O}(s)\) ?

0.001 torr
[latex]10^3[/latex] torr
0.76 torr
1.31 torr

Question 32 of 69

32. Question

\(\mathrm{NH}_4 \mathrm{HS}(\mathrm{s}) \rightleftharpoons \mathrm{NH}_3(\mathrm{~g})+\mathrm{H}_2 \mathrm{~S}(\mathrm{~g})\)

The equilibrium pressure at \(25^{\circ} \mathrm{C}\) is 0.660 atm . What is \(K_p\) for the reaction?

0.109
0.218
1.89
2.18

Question 33 of 69

33. Question

For the reaction \(2 A(\mathrm{~g}) \rightleftharpoons B(\mathrm{~g})+3 C(\mathrm{~g})\), at a given temperature, \(K_c=16\). What must be the volume of the flask, if a mixture of 2 mole each of \(A, B\) and \(C\) exist in equilibrium?

[latex]\frac{1}{4}[/latex]
\(\frac{1}{2}\)
1
None of these

Question 34 of 69

34. Question

One mole of pure ethyl alcohol was treated with one mole of pure acetic acid at \(25^{\circ} \mathrm{C}\). One-third of the acid changes into ester at equilibrium. The equilibrium constant for the reaction will be :

\(\frac{1}{4}\)
2
3
4

Question 35 of 69

35. Question

\(\mathrm{I}_2(a q)+\mathrm{I}^{-}(a q) \rightleftharpoons \mathrm{I}_3^{-}(a q)\). We started with 1 mole of \(\mathrm{I}_2\) and 0.5 mole of \(\mathrm{I}^{-}\)in one litre flask. After equilibrium is reached, excess of \(\mathrm{AgNO}_3\) gave 0.25 mole of yellow precipitate. Equilibrium constant is :

1.33
2.66
2.0
3.0

Question 36 of 69

36. Question

At \(87^{\circ} \mathrm{C}\), the following equilibrium is established.
\(
\mathrm{H}_2(g)+\mathrm{S}(s) \rightleftharpoons \mathrm{H}_2 \mathrm{~S}(g) ; K_c=0.08
\)
If 0.3 mole hydrogen and 2 mole sulphur are heated to \(87^{\circ} \mathrm{C}\) in a 2 L vessel, what will be the concentration of \(\mathrm{H}_2 \mathrm{~S}\) at equilibrium ?

0.011 M
0.022 M
0.044 M
0.08 M

Question 37 of 69

37. Question

In the equilibrium \(2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{SO}_3(\mathrm{~g})\), the partial pressure of \(\mathrm{SO}_2, \mathrm{O}_2\) and \(\mathrm{SO}_3\) are \(0.662,0.10\) and 0.331 atm respectively. What should be the partial pressure of oxygen so that the equilibrium concentrations of \(\mathrm{SO}_2\) and \(\mathrm{SO}_3\) are equal ?

0.4 atm
1.0 atm
0.8 atm
0.25 atm

Question 38 of 69

38. Question

When heated, ammonium carbamate decomposes as follows:
\(
\mathrm{NH}_4 \mathrm{COONH}_2(s) \rightleftharpoons 2 \mathrm{NH}_3(g)+\mathrm{CO}_2(g)
\)
At a certain temperature, the equilibrium pressure of the system is \(0.318 \mathrm{~atm} . K_p\) for the reaction is :

0.128
0.426
[latex]4.76 \times 10^{-3}[/latex]
None of these

Question 39 of 69

39. Question

In a system \(A(s) \rightleftharpoons 2 B(g)+3 C(g)\), if the concentration of \(C\) at equilibrium is increased by a factor of 2 , it will cause the equilibrium concentration of \(B\) to change to :

two times the original value
one half of its original value
[latex]2 \sqrt{2}[/latex] times to the original value
[latex]\frac{1}{2 \sqrt{2}}[/latex] times the original value

Question 40 of 69

40. Question

\(A+B \rightleftharpoons C+D\). If initially the concentration of \(A\) and \(B\) are both equal but at equilibrium concentration of \(D\) will be twice of that of \(A\) then what will be the equilibrium constant of reaction ?

[latex]\frac{4}{9}[/latex]
[latex]\frac{9}{4}[/latex]
[latex]\frac{1}{9}[/latex]
4

Question 41 of 69

41. Question

The equilibrium constant \(K_c\) for the reaction \(\mathrm{SO}_2(g)+\mathrm{NO}_2(g) \rightleftharpoons \mathrm{SO}_3(g)+\mathrm{NO}(g)\) is 16 . If 1 mole of each of all the four gases is taken in \(1 \mathrm{dm}^3\) vessel, the equilibrium concentration of NO would be :

0.4 M
0.6 M
1.4 M
1.6 M

Question 42 of 69

42. Question

On increasing the temperature, the rate of a reaction :

always increases
always decreases
first increases and then decreases
may increase or decrease depending upon the nature of the reaction

Question 43 of 69

43. Question

5 moles of \(\mathrm{SO}_2\) and 5 moles of \(\mathrm{O}_2\) are allowed to react. At equilibrium, it was found that \(60 \%\) of \(\mathrm{SO}_2\) is used up. If the pressure of the equilibrium mixture is one atmosphere, the partial pressure of \(\mathrm{O}_2\) is:

0.52 atm
0.21 atm
[latex]0.41 \mathrm{~atm} \cdot[/latex]
0.82 atm

Question 44 of 69

44. Question

\(\mathrm{N}_2(\mathrm{~g})+3 \mathrm{H}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NH}_3(\mathrm{~g})\)
For the reaction initially the mole ratio was [/latex]1: 3[/latex] of \(\mathrm{N}_2: \mathrm{H}_2\). At equilibrium \(50 \%\) of each has reacted. If the equilibrium pressure is \(P\), the partial pressure of \(\mathrm{NH}_3\) at equilibrium is :

\(\frac{p}{3}\)
[latex]\frac{P}{4}[/latex]
[latex]\frac{P}{6}[/latex]
[latex]\frac{P}{S}[/latex]

Question 45 of 69

45. Question

2.0 mole of \(\mathrm{PCl}_5\) were introduced in a vessel of 5.0 L capacity of a particular temperature. At equilibrium, \(\mathrm{PCl}_5\) was found to be \(35 \%\) dissociated into \(\mathrm{PCl}_3\) and \(\mathrm{Cl}_2\). The value of \(K_c\) for the reaction

\(
\mathrm{PCl}_3(g)+\mathrm{Cl}_2(g) \rightleftharpoons \mathrm{PCl}_5(g)
\)

1.89
0.377
1.33
13.3

Question 46 of 69

46. Question

for the reaction \(\mathrm{I}_2(\mathrm{~g})+\mathrm{CO}_2(\mathrm{~g}) \rightleftharpoons \mathrm{CO}(\mathrm{g})+\mathrm{H}_2 \mathrm{O}(\mathrm{g})\). If the initial concentration of \(\left[\mathrm{H}_2\right]=\left[\mathrm{CO}_2\right]\) and \(x\) moles/litre of hydrogen is consumed at equilibrium, the correct expression of \(K_p\) is :

\(\frac{x^2}{(1-x)^2}\)
[latex]\frac{(1+x)^2}{(1-x)^2}[/latex]
[latex]\frac{x^2}{(2+x)^2}[/latex]
[latex]\frac{x^2}{1-x^2}[/latex]

Question 47 of 69

47. Question

At \(27^{\circ} \mathrm{C}\) and 1 atm pressure, \(\mathrm{N}_2 \mathrm{O}_4\) is \(20 \%\) dissociation into \(\mathrm{NO}_2\). What is the density of equilibrium mixture of \(\mathrm{N}_2 \mathrm{O}_4\) and \(\mathrm{NO}_2\) at \(27^{\circ} \mathrm{C}\) and 1 atm ?

[latex]3.11 \mathrm{~g} /[/latex] litre
2.11 g /litre
4.5 g /litre
None of these

Question 48 of 69

48. Question

\(\mathrm{COCl}_2\) gas dissociates according to the equation, \(\mathrm{COCl}_2(g) \rightleftharpoons \mathrm{CO}(g)+\mathrm{Cl}_2(g)\). When heated to 700 K the density of the gas mixture at 1.16 atm and at equilibrium is \(1.16 \mathrm{~g} /\) litre. The degree of dissociation of \(\mathrm{COCl}_2\) at 700 K is :

0.28
0.50
0.72
0.42

Question 49 of 69

49. Question

The degree of dissociation of \(\mathrm{I}_2\) molecule of \(1000^{\circ} \mathrm{C}\) and under atmospheric pressure is \(40 \%\) by volume. If the dissociation is reduced to \(20 \%\) at the same temp. total equilibrium pressure on the gas is :

1.57 atm
2.57 atm
3.57 atm
4.57 atm

Question 50 of 69

50. Question

Determine the value of equilibrium constant \(\left(K_c\right)\) for the reaction
\(
A_2(g)+B_2(g) \rightleftharpoons 2 A B(g)
\)
If 10 moles of \(A_2 ; 15\) moles of \(B_2\) and 5 moles of \(A B\) are placed in a 2 litre vessel and allowed to come to equilibrium. The final concentration of \(A B\) is 7.5 M :

4.5
1.5
0.6
None of these

Question 51 of 69

51. Question

At \(87^{\circ} \mathrm{C}\), the following equilibrium is established
\(
\mathrm{H}_2(\mathrm{~g})+\mathrm{S}(s) \rightleftharpoons \mathrm{H}_2 \mathrm{~S}(g) ; \quad K_p=7 \times 10^{-2}
\)
If 0.50 mole of hydrogen and 1.0 mole of sulphur are heated to \(87^{\circ} \mathrm{C}\) in 1.0 L vessel, what will be the partial pressure of \(\mathrm{H}_2 \mathrm{~S}\) at equilibrium ?

0.966 atm
1.38 atm
0.0327 atm
1 atm

Question 52 of 69

52. Question

Pure \(\mathrm{PCl}_5\) is introduced into an evacuated chamber and comes to equilibrium at \(247^{\circ} \mathrm{C}\) and 2.0 atm. The equilibrium gaseous mixture contains \(40 \%\) chlorine by volume.
Calculate \(K_p\) at \(247^{\circ} \mathrm{C}\) for the reaction

\(
\mathrm{PCl}_5(g) \rightleftharpoons \mathrm{PCl}_3(g)+\mathrm{Cl}_2(g)
\)

0.625 atm
4 atm
1.6 atm
None of these

Question 53 of 69

53. Question

For the reaction

\(
\mathrm{SnO}_2(s)+2 \mathrm{H}_2(g) \rightleftharpoons 2 \mathrm{H}_2 \mathrm{O}(g)+\mathrm{Sn}(l)
\)

calculate \(K_p\) at 900 K , where the equilibrium steam-hydrogen mixture was \(45 \% \mathrm{H}_2\) by volume :

1.49
1.22
0.67
None of these

Question 54 of 69

54. Question

For the reaction \(\mathrm{XCO}_3(s) \rightleftharpoons \mathrm{XO}(s)+\mathrm{CO}_2(g), K_p=1.642\) atm at \(727^{\circ} \mathrm{C}\). If 4 moles of \(X \mathrm{CO}_3(s)\) was put into a 50 litre container and heated to \(727^{\circ} \mathrm{C}\).
What mole percent of the \(\mathrm{XCO}_3\) remains unreacted at equilibrium?

20
25
50
None of these

Question 55 of 69

55. Question

\(\mathrm{Fe}_2 \mathrm{O}_3(s)\) may be converted to Fe by the reaction

\(
\mathrm{Fe}_2 \mathrm{O}_3(s)+3 \mathrm{H}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{Fe}(s)+3 \mathrm{H}_2 \mathrm{O}(\mathrm{~g})
\)

for which \(K_c=8\) at temp. \(720^{\circ} \mathrm{C}\).
What percentage of the \(\mathrm{H}_2\) remains unreacted after the reaction has come to equilibrium?

[latex]\simeq 22 \%[/latex]
[latex]\approx 34 \%[/latex]
[latex]\simeq 66 \%[/latex]
[latex]\simeq 78 \%[/latex]

Question 56 of 69

56. Question

\(A B_3(g)\) is dissociates as \(A B_3(g) \rightleftharpoons A B_2(g)+\frac{1}{2} B_2(g)\).
When the initial pressure of \(A B_2\) is 800 torr and the total pressure developed at equilibrium is 900 torr. What fraction of \(A B_3(g)\) is dissociated?

[latex]10 \%[/latex]
[latex]20 \%[/latex]
[latex]25 \%[/latex]
[latex]30 \%[/latex]

Question 57 of 69

57. Question

At 1000 K , a sample of pure \(\mathrm{NO}_2\) gas decomposes as :

\(
2 \mathrm{NO}_2(g) \rightleftharpoons 2 \mathrm{NO}(g)+\mathrm{O}_2(g)
[latex]

The equilibrium constant [latex]K_p\) is 156.25 atm . Analysis shows that the partial pressure of \(\mathrm{O}_2\) is 0.25 atm at equilibrium. The partial pressure of \(\mathrm{NO}_2\) at equilibrium is :

0.01
0.02
0.04
None of these

Question 58 of 69

58. Question

Pure nitrosyl chloride \((\mathrm{NOCl})\) gas was heated to \(240^{\circ} \mathrm{C}\) in a 1.0 L container. At equilibrium the total pressure was 1.0 atm and the NOCl pressure was 0.64 atm . What would be the value of \(K_p\) ?

1.02 atm
[latex]16.875 \times 10^{-3} \mathrm{~atm}[/latex]
[latex]16 \times 10^{-2} \mathrm{~atm}[/latex]
None of these

Question 59 of 69

59. Question

At a certain temperature the equilibrium constant \(K_c\) is 0.25 for the reaction

\(
A_2(g)+B_2(g) \rightleftharpoons C_2(g)+D_2(g)
\)
If we take 1 mole of each of the four gases in a 10 litre container, what would be equilibrium concentration of \(A_2(g)\) ?

0.331 M
0.033 M
0.133 M
1.33 M

Question 60 of 69

60. Question

Consider the following reactions. In which cases is product formation favoured by decrease temperature?
(1) \(\mathrm{N}_2(g)+\mathrm{O}_2(g) \rightleftharpoons 2 \mathrm{NO}(g) ; \quad \Delta H^{\circ}=181 \mathrm{~kJ}\)
(2) \(2 \mathrm{CO}_2(g) \rightleftharpoons 2 \mathrm{CO}(g)+\mathrm{O}_2(g) ; \quad \Delta H^{\circ}=566 \mathrm{~kJ}\)
(3) \(\mathrm{H}_2(g)+\mathrm{I}_2(g) \rightleftharpoons 2 \mathrm{HI}(g) ; \quad \Delta H^{\circ}=-9.4 \mathrm{~kJ}\)
(4) \(\mathrm{H}_2(g)+\mathrm{F}_2(g) \rightleftharpoons 2 \mathrm{HF}(g) ; \quad \Delta H^{\circ}=-541 \mathrm{~kJ}\)

1,2
2 only
1, 2, 3
3,4

Question 61 of 69

61. Question

If the pressure in a reaction vessel for the following reaction is increased by decreasing the volume, what will happen to the concentrations of CO and \(\mathrm{CO}_2\) ?

\(
\mathrm{H}_2 \mathrm{O}(g)+\mathrm{CO}(g) \rightleftharpoons \mathrm{H}_2(g)+\mathrm{CO}_2(g)+\text { Heat }
\)

both the \([\mathrm{CO}]\) and \(\left[\mathrm{CO}_2\right]\) will decrease
neither the \([\mathrm{CO}]\) nor the \(\left[\mathrm{CO}_2\right]\) will change
the [latex][\mathrm{CO}][/latex] will decrease and the [latex]\left[\mathrm{CO}_2\right][/latex] will increase
both the [latex][\mathrm{CO}][/latex] and [latex]\left[\mathrm{CO}_2\right][/latex] will increase both the [latex][\mathrm{CO}][/latex] and [latex]\left[\mathrm{CO}_2\right][/latex] will increase

Question 62 of 69

62. Question

Consider the following reaction and determine which of the conditions will shift the equilibrium position to the right?

\(4 \mathrm{NH}_3(g)+5 \mathrm{O}_2(g) \rightleftharpoons 4 \mathrm{NO}(g)+6 \mathrm{H}_2 \mathrm{O}(g)+\text { Heat }
\)

increasing the temperature
increasing the pressure
adding a catalyst
none of these

Question 63 of 69

63. Question

The conversion of ozone into oxygen is exothermic. Under what conditions is ozone the most stable?

\(
2 \mathrm{O}_3(\mathrm{~g}) \rightleftharpoons 3 \mathrm{O}_2(\mathrm{~g})
\)

At low pressure and low temperature
At high pressure and high temperature
At high pressure and low temperature
At low pressure and high temperature

Question 64 of 69

64. Question

For an equilibrium \(\mathrm{H}_2 \mathrm{O}(s) \rightleftharpoons \mathrm{H}_2 \mathrm{O}(l)\), which of the following

The pressure changes do not affect the equilibrium
More of ice melts if pressure on the system is increased
More of liquid freezes if pressure on the system is increased
The pressure changes may increase or decrease the degree of advancement of the process

Question 65 of 69

65. Question

A pressure cooker reduces cooking time for food because:

the higher pressure inside the cooker crushes the food material
cooking involves chemical changes helped by a rise in temperature
heat is more evenly distributed in the cooking space
boiling point of water involved in cooking is increased

Question 66 of 69

66. Question

The vapour pressure of a liquid in a closed container depends on :
(1) temperature of liquid
(2) quantity of liquid
(3) surface area of the liquid

1 only
2 only
1 and 3 only
1, 2 and 3

Question 67 of 69

67. Question

The pressure on a sample of water at its triple point is reduced while the temperature is held constant. Which phases changes are favoured?
(I) melting of ice
(II) sublimation of ice
(III) vaporization of liquid water

I only
III only
II only
II and III

Question 68 of 69

68. Question

Solid \(\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2\) decomposes as

\(
\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2(s) \rightleftharpoons \mathrm{CaCO}_3(s)+\mathrm{CO}_2(g)+\mathrm{H}_2 \mathrm{O}(g)
\)

If the total pressure is 0.2 bar at 420 K , what is the standard free energy change for the given reaction ( \(\Delta_r G^{\circ}\) )?

[latex]840 \mathrm{~kJ} / \mathrm{mol}[/latex]
[latex]3.86 \mathrm{~kJ} / \mathrm{mol}[/latex]
[latex]6.98 \mathrm{~kJ} / \mathrm{mol}[/latex]
[latex]16.083 \mathrm{~kJ} / \mathrm{mol}[/latex]

Question 69 of 69

69. Question

The standard free energy change of a reaction is \(\Delta G^{\circ}=-115 \mathrm{~kJ}\) at 298 K . Calculate the value of \(\log _{10} K_p\left(R=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)\)

20.16
2.303
2.016
13.83