The pH of a buffer solution made by mixing 25 mL of 0.02 M NH₄OH and 25 mL of 0.2 M NH₄Cl at 25° is pK_b of NH₄OH = 4.8)

• 5.8

• 8.2

• 4.8

• 3.8

212.

Which one of the following statements is not correct?

• The pH of 1.0 ×10^-8 M HCl is less than 7.

• The ionic product of water at 25°C is 1.0 ×10^-14 mol²L^-2

• Cl^- is a Lewis acid

• Bronsted Lowry theory cannot explain the acidic character of AlCl₃.

The pK_a values of four carboxylic acids are given below. Identify the weakest carboxylic acid.

• 4.89

• 1.28

• 4.76

• 2.56

On increasing temperature, the equilibrium constant of exothermic and endothermic reactions, respectively

• increases and decreases

• decreases and increases

• increases and increases

• decreases and decreases

What is the pH of the NaOH solution when 0.04 g of it dissolved in water and made to 100 mL solution?

• 2

• 1

• 13

• 12

Which one of the following is correct with respect to basic character?

• P(CH₃)₃ > PH₃

• PH₃ > P(CH₃)₃

• PH₃ > NH₃

• PH₃ = NH₃

If the ionc product of Ni(OH)₂ is 1.9× 10^-15, the molar solubility of Ni(OH)₂ in 1.0 M NaOH

• 1.9 × 10^-18 M

• 1.9 × 10^-13 M

• 1.9 × 10^-15 M

• 1.9 × 10^-15 M

40 mL of x M KMnO₄ solution is required to react completely with 200 mL of 0.02 M oxalic acid solution in acidic medium. The value of x is

• 0.04

• 0.01

• 0.03

• 0.02

At 400 K, in a 1.0 L vessel, N₂O is allowed to attain equilibrium, N₂O₄ (g) $\rightleftharpoons$ 2NO₂ (g)

At equilibrium, the total pressure is 600 mm Hg, when 20% of N₂O₄ is dissociated. The value of K_P for the reaction is

• 50

• 100

• 150

• 200

In which of the following salts, only cationic hydrolysis is involved?

• CH₃COONH₄

• CH₃COONa

• NH₄Cl

• Na₂SO₄