In which of the following mixed aqueous solutions, pH =pK_a at equilibrium?

(1) 100 mL of 0.1 M CH₃COOH +100mL 0.1 M CH₃COONa.

(2) 100 mL of 0.1 M CH₃COOH  + 50 mL of 0.1 M NaOH.

(3) 100 mL of 0.1 M CH₃COOH + 100 mL of 0.1 M NaOH.

(4) 100 mL of 0.1 M CH₃COOH + 100 mL of 0.1 M NH_3.

• (1) is correct

• (2) is correct

• (3) is correct

• Both (1) and (2) are correct

42.

Consider the following salts : NaCl, HgCl₂, Hg₂Cl₂, CuCl₂, CuCl and AgCl.

Identify the correct set of insoluble salts in water.

• Hg₂Cl₂, CuCl, AgCl

• HgCl₂, CuCl_, AgCl

• Hg₂Cl₂, CuCl₂, AgCl

• Hg₂Cl₂, CuCl, NaCl

The ratio of volumes of CH₃COOH 0.1 N to CH₃COONa 0.1 N required to prepare a buffer solution of pH 5.74 is (Given, pK_a of CH₃COOH is 4.74)

• 10 : 1

• 5 : 1

• 1 : 5

• 1 : 10

Within the list shown below, the correct pair of structures of alanine in pH ranges 2-4 and 9-11 is

I. H₃N⁺ - CH(CH₃)CO₂H

II. H₂N - CH(CH₃)CO${}_2^{-}$

III. H₃N⁺-CH(CH₃)CO${}_2^{-}$

IV. H₂N-CH(CH₃)CO₂H

• I and II

• I and III

• II and III

• III and IV

The correct statement regarding the following energy diagrams is

• Reaction M is faster and less exothermic than reaction N

• Reaction M is slower and less exothermic than reaction N

• Reaction M is faster and more exothermic than reaction N

• Reaction M is slower and more exothermic than reaction N

At 25°C, the solubility product of salt of MX₂ type is 3.2 × 10^-8 in water. The solubility (in mol/L) of MX₂ in water at the same temperature will be

• 1.2 × 10^-3

• 2 × 10^-3

• 3.2 × 10^-3

• 1.75 × 10^-3

The different colours of litmus in acidic, neutral and basic solutions are, respectively.

• red, orange and blue

• blue, violet and red

• red, colourless and blue

• red, violet and blue

The correct order of equivalent conductances at infinite dilution in water at room temperature for H⁺, K⁺, CH₃COO^- and HO^- ions is

• HO^- > H⁺ > K⁺ > CH₃COO^-

• H⁺ > HO^- > K⁺ > CH₃COO^-

• H⁺ > K⁺ > HO^- > CH₃COO^-

• H⁺ > K⁺ > CH₃COO^- > HO^-

The pH of 10^-4 M KOH solution will be

• 4

• 11

• 10.5

• 10

For a chemical reaction at 27°C, the activation energy is 600 R. The ratio of the rate constants at 327°C to that of at 27°C will be

• 2

• 40

• e

• e²