Equilibrium

Calculate pH of a buffer prepared by adding 10 mL of 0.10 M acetic acid to 20 mL of 0.1 M sodium acetate [ pK_a (CH₃COOH) = 4.74 ]

• 3.00

• 4.44

• 4.74

• 5.04

The degree of dissociation of a 0.01 M weak acid is 10^-3. Its pOH is

• 5

• 3

• 9

• 11

0.1 M solution of which of the following has almost unity degree of dissociation ?

• Ammonium chloride

• Potassium chloride

• Sodium acetate

• All of the above

If 20 mL of an acidic solution of pH 3 is diluted to 100 mL, the H⁺ ion concentration will be

• 1 × 10^-3 M

• 2 × 10^-3 M

• 2 × 10^-4 M

• 0.02 × 10^-4 M 

If $∆\mathrm{E}$  is the heat of reaction for

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right) + 3{\mathrm{O}}_2\left(\mathrm{g}\right) \to 2{\mathrm{CO}}_2\left(\mathrm{g}\right) + 3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \mathrm{at} \mathrm{constant} \mathrm{volume}, \mathrm{the} ∆\mathrm{H}$ (heat of reaction at constant pressure), at constant temperature is

• $∆\mathrm{H} = ∆\mathrm{E} + \mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} - \mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} - 2\mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} + 2\mathrm{RT}$

Which one of the following species acts as both Bronsted acid and base?

• ${\mathrm{H}}_2{\mathrm{PO}}_2^{-}$

• ${\mathrm{HPO}}_3^{2-}$

• ${\mathrm{HPO}}_4^{2-}$

• All of these

The number of hydroxyl ions in 10 cm³ of 0.2 M HCl solution is

• 5 × 10^-14

• 3 × 10⁹

• 3 × 10¹²

• 5 × 10^-12

Solubility of Ca(OH)₂ is s mol L^-1. The solubility product (K_sp) under the same condition is

• 4s³

• 3s⁴

• 4s²

• s³

The pH of a 0.1 M solution of NH₄OH (having K_b =1.0 x 10^-5) is equal to

• 10

• 6

• 11

• 12

Which of the following salts will not undergo hydrolysis?

• NH₄Cl

• KCN

• KNO₃

• Na₂CO₃