Q. No.Find concentration of \(X^{2-}\) at equilibrium in 0.1 M \(H_2X\) ? (in order of \(10^{-15}\))
[Given: \(K_{a_1}=2.5 \times 10^{-8}, K_{a_2}=1 \times 10^{-13} .\)]
1. 100
2. 1000
3. 400
4. 250
[Given: \(K_{a_1}=2.5 \times 10^{-8}, K_{a_2}=1 \times 10^{-13} .\)]
1. 100
2. 1000
3. 400
4. 250
Subtopic: Ionisation Constant of Acid, Base & Salt |
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Level 3: 35%-60%
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Hints
Two moles each of the gases \(P_2, Q_2\) and PQ are present in a vessel at equilibrium. If 1 mole each of \(P_2\) and \(Q_2\) is added at equilibrium, then determine the composition (in mole) of each species at the new equilibrium ?
1. \(\mathrm{n}_{\mathrm{P}_2}=0.5, \mathrm{n}_{\mathrm{Q}_2}=0.5, \mathrm{n}_{\mathrm{PQ}}=1 \)
2. \(\mathrm{n}_{\mathrm{P}_2}=1.33, \mathrm{n}_{\mathrm{Q}_2}=1.33, \mathrm{n}_{\mathrm{PQ}}=1.67\)
3. \(\mathrm{n}_{\mathrm{P}_2}=2.67, \mathrm{n}_{\mathrm{O}_2}=2.67, \mathrm{n}_{\mathrm{PQ}}=2.33 \)
4. \(\mathrm{n}_{\mathrm{P}_2}=2.67, \mathrm{n}_{\mathrm{Q}_2}=2.67, \mathrm{n}_{\mathrm{PQ}}=2.67\)
1. \(\mathrm{n}_{\mathrm{P}_2}=0.5, \mathrm{n}_{\mathrm{Q}_2}=0.5, \mathrm{n}_{\mathrm{PQ}}=1 \)
2. \(\mathrm{n}_{\mathrm{P}_2}=1.33, \mathrm{n}_{\mathrm{Q}_2}=1.33, \mathrm{n}_{\mathrm{PQ}}=1.67\)
3. \(\mathrm{n}_{\mathrm{P}_2}=2.67, \mathrm{n}_{\mathrm{O}_2}=2.67, \mathrm{n}_{\mathrm{PQ}}=2.33 \)
4. \(\mathrm{n}_{\mathrm{P}_2}=2.67, \mathrm{n}_{\mathrm{Q}_2}=2.67, \mathrm{n}_{\mathrm{PQ}}=2.67\)
Subtopic: Ionisation Constant of Acid, Base & Salt |
60%
Level 2: 60%+
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Hints
For the reaction:
\(\begin{array}{ll} \mathrm{A}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{~A}(\mathrm{~g}) \\ \Delta \mathrm{G}_{\mathrm{f}\left(\mathrm{~A}_2\right)}^{\circ}=-100 \mathrm{KJ} / \mathrm{mol} \\ & \\ \Delta\mathrm{G}_{\mathrm{f}(\mathrm{~A})}^{\circ}=-50.8625 \mathrm{KJ} / \mathrm{mol} \end{array}\)
At 300K and 1 atm, degree of dissociation of \(A_2\) gas at equilibrium is \(x\times 10^{-2}.\) Find x:\(\left[\mathrm{R}=8.3 ~\mathrm{Jmol}^{-1} \mathrm{~K}^{-1}\right]\)
1. 52.70
2. 55.18
3. 57.73
4. 59.30
\(\begin{array}{ll} \mathrm{A}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{~A}(\mathrm{~g}) \\ \Delta \mathrm{G}_{\mathrm{f}\left(\mathrm{~A}_2\right)}^{\circ}=-100 \mathrm{KJ} / \mathrm{mol} \\ & \\ \Delta\mathrm{G}_{\mathrm{f}(\mathrm{~A})}^{\circ}=-50.8625 \mathrm{KJ} / \mathrm{mol} \end{array}\)
At 300K and 1 atm, degree of dissociation of \(A_2\) gas at equilibrium is \(x\times 10^{-2}.\) Find x:\(\left[\mathrm{R}=8.3 ~\mathrm{Jmol}^{-1} \mathrm{~K}^{-1}\right]\)
1. 52.70
2. 55.18
3. 57.73
4. 59.30
Subtopic: Ionisation Constant of Acid, Base & Salt | Solubility Product |
Level 3: 35%-60%
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Hints
For a given reaction, \( K_P=9~\text{atm}\)
\(\mathrm{NH}_{3(\mathrm{~g})} \rightleftharpoons \frac{1}{2} \mathrm{~N}_{2(\mathrm{~g})}+\frac{3}{2} \mathrm{H}_{2(\mathrm{~g})}\)
Total pressure at equilibrium is \(\sqrt 3\) atm.
Find the value of \(7~\alpha ^2,\) where \(\alpha \) is degree of dissociation of \(NH_{3(g)}?\)
1. 2.8
2. 5.2
3. 5.6
4. 8.4
\(\mathrm{NH}_{3(\mathrm{~g})} \rightleftharpoons \frac{1}{2} \mathrm{~N}_{2(\mathrm{~g})}+\frac{3}{2} \mathrm{H}_{2(\mathrm{~g})}\)
Total pressure at equilibrium is \(\sqrt 3\) atm.
Find the value of \(7~\alpha ^2,\) where \(\alpha \) is degree of dissociation of \(NH_{3(g)}?\)
1. 2.8
2. 5.2
3. 5.6
4. 8.4
Subtopic: Kp, Kc & Factors Affecting them | Ionisation Constant of Acid, Base & Salt |
57%
Level 3: 35%-60%
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Consider the reaction:
\(\mathrm{X}_2 \mathrm{Y}(\mathrm{~g}) \rightleftharpoons \mathrm{X}_2(\mathrm{~g})+\frac{1}{2} \mathrm{Y}_2(\mathrm{~g})\)
The equation representing the correct relationship between the degree of dissociation (x) of X2Y(g) with its equilibrium constant Kp is:
(Assume x to be very very small)
\(\mathrm{X}_2 \mathrm{Y}(\mathrm{~g}) \rightleftharpoons \mathrm{X}_2(\mathrm{~g})+\frac{1}{2} \mathrm{Y}_2(\mathrm{~g})\)
The equation representing the correct relationship between the degree of dissociation (x) of X2Y(g) with its equilibrium constant Kp is:
(Assume x to be very very small)
| 1. | \(\mathrm{x}=\sqrt[3]{\dfrac{2 \mathrm{Kp}}{\mathrm{p}}}\) | 2. | \(x=\sqrt[3]{\dfrac{2 \mathrm{Kp}^2}{\mathrm{p}}}\) |
| 3. | \(x=\sqrt[3]{\dfrac{\mathrm{Kp}}{2 \mathrm{p}}}\) | 4. | \(x=\sqrt[3]{\dfrac{K p}{p}}\) |
Subtopic: Kp, Kc & Factors Affecting them | Ionisation Constant of Acid, Base & Salt |
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If 1 mM solution of ethylamine produces pH = 9, then the ionization constant (Kb) of ethylamine is 10–x.
The value of x is: (nearest integer)
[Note: The degree of ionization of ethylamine can be neglected with respect to unity]
1. 5
2. 7
3. 9
4. 11
The value of x is: (nearest integer)
[Note: The degree of ionization of ethylamine can be neglected with respect to unity]
1. 5
2. 7
3. 9
4. 11
Subtopic: Ionisation Constant of Acid, Base & Salt | pH calculation |
70%
Level 2: 60%+
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For a weak acid HA with a degree of dissociation x, which of the following gives the correct expression for \((\text{pH} - \text{pKa})\)?
| 1. | log (1+2x) | 2. | \(\log \left(\dfrac{1-x}{x}\right)\) |
| 3. | 0 | 4. | \(\log \left(\dfrac{x}{1-x}\right)\) |
Subtopic: Ionisation Constant of Acid, Base & Salt |
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At \(\mathrm{298~K},\) The equilibrium constant is \(2 \times10^{15}\) for the reaction: \(\mathrm{Cu}(\mathrm{s})+2 \mathrm{Ag}^{+}(\mathrm{aq}) \rightleftharpoons \mathrm{Cu}^{2+}(\mathrm{aq})+2 \mathrm{Ag}(\mathrm{s})\).
If the equilibrium constant for the reaction \(\frac{1}{2} \mathrm{Cu}^{2+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s}) \rightleftharpoons \frac{1}{2} \mathrm{Cu}(\mathrm{s})+\mathrm{Ag}^{+}(\mathrm{aq})\) is \(x \times 10^{-8}\), then find the value of \(\mathrm{x}\) in nearest integer form:
1. Eight (8)
2. Five (5)
3. Six (6)
4. Two (2)
If the equilibrium constant for the reaction \(\frac{1}{2} \mathrm{Cu}^{2+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s}) \rightleftharpoons \frac{1}{2} \mathrm{Cu}(\mathrm{s})+\mathrm{Ag}^{+}(\mathrm{aq})\) is \(x \times 10^{-8}\), then find the value of \(\mathrm{x}\) in nearest integer form:
1. Eight (8)
2. Five (5)
3. Six (6)
4. Two (2)
Subtopic: Ionisation Constant of Acid, Base & Salt |
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Level 2: 60%+
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What is the number of moles of \(NH_3\) that must be added to \(2L\) of \(0.8~M~AgNO_3\) in order to reduce the concentration of \(Ag^+\) ions to \(5.0 \times 10^{-8} \mathrm{M}\) ? [Assume no volume change on adding \(NH_3]\)
[Given : \(\mathrm{K}_{\text {formation }} \text { for }\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}=1.0 \times 10^8\)]
[Report your answer in the nearest integer]
1. Two (2)
2. Four (4)
3. Eight (8)
4. One (1)
[Given : \(\mathrm{K}_{\text {formation }} \text { for }\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}=1.0 \times 10^8\)]
[Report your answer in the nearest integer]
1. Two (2)
2. Four (4)
3. Eight (8)
4. One (1)
Subtopic: Ionisation Constant of Acid, Base & Salt |
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Sodium oxide reacts with water to produce sodium hydroxide. If \(200 ~\text{g}\) of sodium oxide is dissolved in \(500 ~\text{mL}\) of water, then what is the concentration of the resulting \(\text{NaOH}\) solution?
[Note: Neglect the change in volume]
[Atomic mass; \(\mathrm{Na=23.0,O=16.0,H=1.0]}\)
1. 11
2. 12
3. 13
4. 14
[Note: Neglect the change in volume]
[Atomic mass; \(\mathrm{Na=23.0,O=16.0,H=1.0]}\)
1. 11
2. 12
3. 13
4. 14
Subtopic: Ionisation Constant of Acid, Base & Salt |
52%
Level 3: 35%-60%
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