PbCl₂ is insoluble in cold water. Addition of HCl increases its solubility due to

• formation of soluble complex anions like [PbCl₃]^-

• oxidation of Pb(II) to PB(IV)

• formation of [Pb(H₂O)₆]²⁺

• formation of polymeric lead complexes

Of the following compounds, which one is the strongest Bronsted acid in a aqueous solution?

• HClO₃

• HClO₂

• HOCl

• HOBr

The yield of acetanilide in the reaction (100% conversion) of 2 moles of aniline with 1 mole of acetic anhydride is

• 270 gm

• 135 gm

• 67.5 gm

• 177 gm

Equilibrium constants for the following reactions at 1200 K are given

2H₂O (g) $\rightleftharpoons$ 2H₂ (g) + O₂ (g)    [K₁ = 6.8 × 10^-8]

2CO₂ (g) $\rightleftharpoons$ 2CO (g) + O₂ (g)    [K₂ = 1.6 × 10^-6]

The equilibrium constant for the reaction?

H₂(g) + CO₂(g) $\rightleftharpoons$ CO (g) + H₂O (g)

at 1200 K will be

• 0.05

• 20

• 0.2

• 5.0

Which of the following solutions will turn violet when a drop of lime juice is added to it?

• A solution of NaI

• A solution mixture of KI and NaIO₃

• A solution mixture of NaI and KI

• A solution mixture of KIO₃ and NaIO₃

The molar solubility (in mol L^-1) of a sparingly soluble salt MX₄ is 'S'. The corresponding solubility product is K_sp in terms of 'K_sp' is given by the relation

• $\mathrm{S}={\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{128}\right)}^{1/4}$

• $\mathrm{S}={\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{256}\right)}^{1/5}$

• S=(256 K_sp)^1/5

• S=(128 K_sp)^1/4

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

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