When 0.1 mole of CH₃NH₂ (ionization constant ${\mathrm{K}}_{\mathrm{b}}=5\times {10}^{-4}$) is mixed with 0.08 mol HCl and the volume is made up of 1 litre. The [H⁺] of resulting solution is -

(log 4 =  0.60)

1. $8\times {10}^{-2}$

2. $2\times {10}^{-11}$

3. $1.23\times {10}^{-4}$

4. $8\times {10}^{-11}$

The solution with pH value close to 1.0 among the following is:

If \(Ag^+ + 2NH_3 \rightleftharpoons Ag(NH_3)_2^+ : K_1 = 1.8 \times 10^7\)
\(Ag^+ + Cl^-\rightleftharpoons AgCl : K_2 =5.6 \times 10^9\)
Then for \(AgCl + 2 NH_3 \rightleftharpoons [Ag(NH_3)_2]^+ + Cl^-\)
Equilibrium constant will be:
1. \(0.32 \times 10^{-2}\)
2. \(3.11 \times 10^2 \)
3. \(10.08 \times 10^{16} \)
4. \(1.00 \times 10^{-17}\)

Three sparingly soluble salts A₂X, AX, and AX₃ have the same solubility product. Their solubilities will be in the order:

1. AX₃>AX>A₂X

2. AX₃ < A₂X>AX

3. AX>AX₃>A₂X

4. AX>A₂X>AX₃

Which of the following solution(s) have pH between 6 and 7?
I. \(2 \times 10^{-6}~ \text {M NaOH}\)
II. \(2 \times 10^{-6}~ \text {M HCl}\)
III. \( 10^{8}~ \text {M HCl}\)
IV. \(10^{-13}~ \text {M NaOH}\)

1. I, II
2. III only
3. III, IV
4. II, III, IV

At what pH does Mg(OH)₂ start to precipitate from a solution with 0.10 M Mg²⁺ ions, given that the Ksp of Mg(OH)₂ is 1 × 10⁻¹¹?

1. 3

2. 6

3. 9

4. 11

50 litres of 0.1 M HCl are mixed with 50 litres of 0.2 M NaOH. The pH of the resulting solution will be:

1. 12.70

2. 12.34

3. 8.7

4. 4.2

The pH of a 0.05 M aqueous solution of diethylamine is 12. Its K_b value will be:

1. $2\times {10}^{-3}$

2. $2.5\times {10}^{-3}$

3. $3\times {10}^{-3}$

4. $4.5\times {10}^{-3}$

K_a for HCN is $5\times {10}^{-10}$ at $25°\mathrm{C}$. For maintaining a constant pH of 9, the volume of 5 M KCN solution required to be added to 10 mL of 2 M HCN solution is-

1. 2 mL

2. 3 mL

3. 4.2 mL

4. 5.6 mL

The approximate pH of a solution formed by mixing equal volumes of solutions of 0.1 M sodium propionate and 0.1 M propanoic acid (the dissociation constant of propanoic acid is \(1.3 \times 10^{-5}~ \text {mol dm}^{-3}\)${\mathrm{}}^{}$)  will be: