For a reaction, 2NO (g) + Br2 (g)  2NOBr (g)

When 0.087 mol of NO and 0.0437 mol of Br2 are mixed in a closed container of volume 1 litre at a constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. The concentration of NO and Br2 at equilibrium will be:

1. NO = 0.0352 mol; Br2= 0.0178 mol

2. NO = 0.352 mol; Br2= 0.178 mol

3. NO = 0.0634 mol; Br2= 0.0596 mol

4. NO = 0.634 mol; Br2= 0.596 mol

Subtopic:  Introduction To Equilibrium |
 73%
Level 2: 60%+
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For the reaction: H2 (g) + I2 (g)  ⇌ 2HI (g) ; Kc54.8 at 700K .

If 0.5 mol L–1 of HI(g) is present at equilibrium at 700 K, the concentration of H2(g) and I2(g)  would be:

1. [H2]= [I2]=0.05 mol L-1

2. [H2]= 0.5 mol L-1, [I2] = 0.05 mol L-1

3. [H2] = 0.068 mol L-1, [I2]= 0.55 mol L-1

4. [H2] = [I2] =0.068 mol L-1

Subtopic:  Kp, Kc & Factors Affecting them |
 68%
Level 2: 60%+
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What will be the equilibrium concentration of ICl when its initial concentration is 0.78 M for the reaction:
2ICl(g) ⇋ I
2(g) + Cl2(g); Kc = 0.14 ?

1. 0.446 M 2. 0.876 M
3. 0.345 M 4. 0.986 M
Subtopic:  Kp, Kc & Factors Affecting them |
 56%
Level 3: 35%-60%
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Given the reaction:
CH
3COOH(l) + C2H5OH(l)  CH3COOC2H5(l) + H2O(l)

At 293 K, a mixture is prepared starting with 1.00 mol of acetic acid and 0.18 mol of ethanol.
At equilibrium, 0.171 mol of ethyl acetate is formed.
Calculate the equilibrium constant (Kc) for the reaction.

1. 0.78

2. 1.3

3. 2.47

4. 3.92
Subtopic:  Kp, Kc & Factors Affecting them |
 52%
Level 3: 35%-60%
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(a) PCl5 (g) PCl3 (g) + Cl2 (g)

(b) CaO (s) + CO2 (g)   CaCO3 (s)

(c) 3Fe (s) + 4H2O (g)  Fe3O4 (s) + 4H2 (g)

The effect of an increase in the volume on the number of moles of products in the above-mentioned reactions would be, respectively:

1. a) Increase,  b) decrease, c) same

2. a) Decrease,  b) same, c) increase

3. a) Increase,  b) increase, c) same

4. a) Increase,  b) decrease, c) increase

Subtopic:  Le Chatelier's principle |
 74%
Level 2: 60%+
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Consider the following reactions:

(i) COCl2 (g)  ⇋ CO (g) + Cl2 (g)

(ii) CO2 (g) + C (s)  2CO (g)

(iii) 2H2 (g) + CO (g)  CH3OH (g)


Which reaction(s) will shift in a backward direction when the pressure is increased?

1. Only (iii)

2. Only (ii)

3. Both (i) and (ii) 

4. None of the above.

Subtopic:  Le Chatelier's principle |
 76%
Level 2: 60%+
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Given an endothermic reaction:

CH4 (g) + H2O (g)  ⇋ CO (g) + 3H2 (g)

If the temperature is increased, then:

1. The equilibrium will not be disturbed.

2. The equilibrium will shift in the backward direction.

3. The equilibrium will shift in the forward direction.

4. None of the above.

Subtopic:  Le Chatelier's principle |
 82%
Level 1: 80%+
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For the given reaction: 

PCl5 (g)  PCl3 (g) + Cl2 (g), ∆r = 124.0 kJ mol–1 and Kc = 8.3 × 10-3 mol L-1 at 473 K

The effect on Kc if (i) pressure is increased  and (ii) the temperature is increased will be, respectively-

1. (i) Will increase; (ii) will decrease

2. (i) Will decrease; (ii) will remain the same 

3. (i) Will remain the same; (ii) will increase

4. (i) will remain the same; (ii) Will decrease

Subtopic:  Kp, Kc & Factors Affecting them |
 77%
Level 2: 60%+
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The conjugate acid-base pair is:

1. A pair that differs only by one proton

2. A pair that differs only by the size

3. A pair that differs only by electronegativity

4. None of the above

Subtopic:  Acids & Bases - Definitions & Classification |
 92%
Level 1: 80%+
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What are the conjugate bases of the Brönsted acids \(\mathrm{H}_2 \mathrm{SO}_4\), and \(\mathrm{HCO}_3^{-}\) respectively?
1. \(\mathrm{HSO}_4^{-}, \mathrm{CO}_3^{2-}\)
2. \(\mathrm{HSO}_4^{-}, \mathrm{CO}_3^{-}\)
3. \(\mathrm{SO}_4^{2-}, \mathrm{CO}_3{ }^{2-}\)
4. \(\mathrm{HS}_2 \mathrm{O}_4{ }^{-}, \mathrm{CO}_3{ }^{2-}\)
Subtopic:  Acids & Bases - Definitions & Classification |
 86%
Level 1: 80%+
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