pH of a buffer solution decreases by 0.02 units when 0.12 g of acetic acid is added to 250 mL of a buffer solution of acetic acid and potassium acetate at 27°C. The buffer capacity of the solution is

• 0.1

• 10

• 1

• 0.4

The equilibnum constant for the given reaction is 100.

N₂ (g) + 2O₂ (g) $\rightleftharpoons$ 2NO₂ (g)

What is the equilibrium constant for the reaction given below?

NO₂ (g) $\rightleftharpoons \frac{1}{2}{\mathrm{N}}_2$ (g) + O₂ (g)

• 10

• 1

• 0.1

• 0.01

20 mL of 0.1 M acetic acid is mixed with 50 mL of potassium acetate. K_a of acetic acid = 1.8 × 10^-5 at 27°C. Calculate concentration of potassium acetate if pH of the mixture is 4.8.

• 0.1 M

• 0.04 M

• 0.4 M

• 0.02 M

If the equilibrium constant for the reaction,

2AB  A₂ + B₂ 

is 49, what is the equilibrium constant for AB $$ \rightleftharpoons \frac{1}{2}{\mathrm{A}}_1 + \frac{1}{2}{\mathrm{A}}_2${\mathrm{}}_{}$ ? 

• 7

• $\frac{1}{7}$

• 24.5

• 49

The pH of 0.05 M acetic acid is K_a = 2 × 10^-5)

• 2

• 11

• 10^-3

• 3

The degree of ionization of 0.10 M lactic acid is 4.0%

The value of K_c is

• 1.66 × 10^-5

• 1.66 × 10^-4

• 1.66 × 10^-3

• 1.66 × 10^-2

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

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