An incorrect statement about equilibrium among the following is:

1.	Equilibrium is possible only in a closed system at a constant 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.

An incorrect statement about equilibrium among the following is:

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
\(\underset{\Large{pink}}{[Co(H_2O)_6]^{3+} (aq)} + 4Cl^-(aq) \rightleftharpoons \underset{\Large{blue}}{[CoCl_4]^{2-} (aq)} + 6H_2O(l)\)

On the basis of the information given above, mark the correct answer:

The pH of neutral water at $25°\mathrm{C}$ 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 ?

${\mathrm{K}}_{{\mathrm{a}}_1},$ ${\mathrm{K}}_{{\mathrm{a}}_2}$ $\mathrm{and}$ ${\mathrm{K}}_{{\mathrm{a}}_3}$ are the respective ionisation constants for the following reactions.
\(\mathrm{H}_2 \mathrm{~S} \rightleftharpoons \mathrm{H}^{+}+\mathrm{HS}^{-}\)
\(\mathrm{HS}^{-} \rightleftharpoons \mathrm{H}^{+}+\mathrm{S}^{2-}\)
\(\mathrm{H}_2 \mathrm{~S} \rightleftharpoons 2 \mathrm{H}^{+}+\mathrm{S}^{2-}\)
The correct relationship between ${\mathrm{K}}_{{\mathrm{a}}_1},$ ${\mathrm{K}}_{{\mathrm{a}}_2}$ $\mathrm{and}$ ${\mathrm{K}}_{{\mathrm{a}}_3}$ is:
1. \(\mathrm{K}_{\mathrm{a}_3}=\mathrm{K}_{\mathrm{a}_1} \times \mathrm{K}_{\mathrm{a}_2} \)
2. \(\mathrm{K}_{\mathrm{a}_3}=\mathrm{K}_{\mathrm{a}_1}+\mathrm{K}_{\mathrm{a}_2} \)
3. \(K_{a_3}=K_{a_1}-K_{a_2} \)
4. \(\mathrm{K}_{\mathrm{a}_3}=\mathrm{K}_{\mathrm{a}_1} / \mathrm{K}_{\mathrm{a}_2}\)

The mixture that will produce a buffer solution when mixed in equal volumes is:

${\mathrm{}}_{}$
Find the pH of ammonium acetate solution when the value of Ka for CH₃COOH is 1.8 × 10⁻⁵
and Kb for NH₄OH is 1.8 × 10⁻⁵.

1. 7.005

2. 4.75

3. 7.0

4. Between 6 and 7

On increasing the pressure, the direction in which the gas phase reaction proceeds to re-establish equilibrium is predicted by applying Le-Chatelier's principle. Consider the reaction,

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

Which of the following is correct, if the total pressure at which the equilibrium is established is increased without changing the temperature?

Find the equilibrium constant (K_c) at 500 K for:

2HI(g) ⇌ H₂(g) + I₂(g)

given that:

½H₂(g) + ½I₂(g) ⇌ HI(g), K_c = 5
 

1. 0.04

2. 0.4

3. 25

4. 2.5