100 ml of 0.3 M NH₄OH is mixed with 100 ml of 0.2 M NaOH. K_b NH₄OH is $1.8\times {10}^{-5}$. The degree of dissociation of NH₄OH is:

1. $1.02\times {10}^{-2}$

2. $1.8\times {10}^{-5}$

3. $1.8\times {10}^{-4}$

4. $1.02\times {10}^{-4}$

Find the rate constant (in L mol⁻¹ s⁻¹) for proton transfer from water to NH₃ at 25°C, given:

Ionization constant of NH₄⁺ in water = 5.6 × 10⁻¹⁰
Rate constant for NH₄⁺ + OH⁻ → NH₃ + H₂O = 3.4 × 10¹⁰ L mol⁻¹ s⁻¹
1. 6.07 × 10⁻⁵
2. 6.07 × 10⁵
3. 3.07 × 10⁻³
4. 3.07 × 10⁻⁴

The equilibrium constant of ${\mathrm{NH}}_4^{+}$ to NH₃ and H⁺ is 10^-10. The rate constant for ${\mathrm{NH}}_4^{+}+{\mathrm{OH}}^{-}\to {\mathrm{NH}}_3+{\mathrm{H}}_2\mathrm{O}$ is 10¹⁰.
The rate constant for ${\mathrm{NH}}_3+{\mathrm{H}}_2\mathrm{O}\to {\mathrm{NH}}_4^{+}+{\mathrm{OH}}^{-}$ is:

1. ${10}^5$

2. ${10}^{20}$

3. ${10}^8$

4. ${10}^9$

Find the change in pH required to convert an indicator (Ka = 3 × 10⁻⁵) from a state where 75% is in acid form (red) to a state where 75% is in base form (blue), given log 3 = 0.4770:

1. 0.95

2. 2.3

3. 0.75

4. 5.0

The dissociation constants for aniline, acetic acid and ionic product of water at $25°\mathrm{C}$ are $3.83\times {10}^{-10},<mspace\; width="1em"></mspace>1.75\times {10}^{-5}<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>1.008\times {10}^{-14}$ respectively. The degree of hydrolysis of aniline acetate in a decinormal solution is

1. 0.56%

2. 55%

3. 5.6%

4. 2.75%

A solution of benzoic acid (a weak monobasic acid) is titrated with NaOH. The pH of the solution is 4.2 when half of the acid is neutralized. The dissociation constant of the acid will be:

1. $3.2\times {10}^{-5}$

2. $6.42\times {10}^{-4}$

3. $6.31\times {10}^{-5}$

4. $8.7\times {10}^{-8}$

The mixture that shows the maximum buffer capacity is:

The pH of a solution containing 0.1 mol of CH₃COOH, 0.2 mol of CH₃COONa, and 0.05 mol of NaOH in 1 L of solution is-

(pK_a of CH₃COOH=4.74 and log 5=0.7)

1. 4.56

2. 5.44

3. 5.04

4. 3.74

Find the pH of a mixture of acetic acid and sodium acetate, given that 18 mL of the mixture requires 6 mL of 0.1 M NaOH for neutralization of the acid and 12 mL of 0.1 M HCl for reaction with the salt separately. The pKa of acetic acid is 4.75.

1. 5.05

2. 4.75

3. 4.50

4. 4.60

What is the minimum pH required to prevent the precipitation of ZnS in a solution containing 0.01 M ZnCl₂ and saturated with 0.10 M H₂S?

(Given: Ksp of ZnS = 10⁻²¹, and Ka₁ × Ka₂ of H₂S = 10⁻²⁰)

1. Four (4)

2. Three (3)

3. Two (2)

4. One (1)