Q. No.
Assertion (A):
An aqueous solution of ammonium acetate can act as a buffer.
Reason (R):
Acetic acid is a weak acid and NH4OH is a weak base.
1.
Both (A) and (R) are True and (R) is the correct explanation of (A).
2.
Both (A) and (R) are True but (R) is not the correct explanation of (A).
3.
(A) is True but (R) is False.
4.
(A) is False but (R) is True.
Given below are two statements:
| Assertion (A): | In the dissociation of PCl5 at constant pressure and temperature, the addition of helium at equilibrium increases the dissociation of PCl5. |
| Reason (R): | Helium reacts with Cl2 . |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
For the reaction , the standard free energy is . The equilibrium constant () would be :
| 1. | \(K_{c}\)=0 | 2. | \(K_{c}\)>1 |
| 3. | \(K_{c}\)=1 | 4. | \(K_{c}\)<1 |
| 1. | Equilibrium is possible only in a closed system at a given temperature. |
| 2. | All measurable properties of the system remain constant. |
| 3. | All the physical processes stop at equilibrium. |
| 4. | The opposing processes occur at the same rate and there is a dynamic but stable condition. |
PCl5, PCl3, and Cl2 are at equilibrium at 500 K in a closed container and their concentrations are 0.8×10–3 mol L–1 , 1.2×10–3 mol L–1 and 1.2×10–3 mol L–1, respectively.
The value of Kc for the reaction PCl5(g) ⇌ PCl3(g) + Cl2(g) will be:
1. 1.8 × 103 mol L–1
2. 1.8 × 103
3. 1.8 × 10–3 mol L–1
4. 0.55 × 104
An incorrect statement about equilibrium among the following is:
| 1. | In equilibrium mixture of ice and water kept in perfectly insulated flask, the mass of ice and water does not change with time. |
| 2. | The intensity of the red colour increases when oxalic acid is added to a solution containing iron (III) nitrate and potassium thiocyanate. |
| 3. | On the addition of a catalyst, the equilibrium constant value is not affected. |
| 4. | The equilibrium constant for a reaction with a negative ∆H value decreases as the temperature increases. |
When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink
\([Co(H_2O)_6]^{3+} (aq) + 4Cl^-(aq) \rightleftharpoons [CoCl_4]^{2-} (aq) + 6H_2O(l)\\ ~~~\small{(Pink})~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\small{ (Blue)}\)
On the basis of the information given above, mark the correct answer:
| 1. | ∆ H > 0 for the reaction |
| 2. | ∆ H < 0 for the reaction |
| 3. | ∆ H = 0 for the reaction |
| 4. | The sign of ∆ H cannot be predicted on the basis of the given information. |
The pH of neutral water at is 7.0. As the temperature increases, ionisation of water increases. However, the concentration of H+ ions and OH- ions is equal. What will be the pH of pure water at 60°C ?
| 1. | Equal to 7.0 | 2. | Greater than 7.0 |
| 3. | Less than 7.0 | 4. | Equal to zero |
The ionisation constant of an acid, Ka , is the measure of the strength of an acid. The Ka values of acetic acid, hypochlorous acid and formic acid are and , respectively. The correct order of pH value of 0.1 mol dm-3 solutions of these acids is:
1. Acetic acid > Hypochlorous acid > Formic acid
2. Hypochlorous acid < Acetic acid > Formic acid
3. Formic acid > Hypochlorous acid > Acetic acid
4. Formic acid < Acetic acid < Hypochlorous acid
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