131.

The low solubility of LiF and that of CsI in water are respectively due to which of the following properties of the alkali metal ions?

• Higher hydration enthalpy of Li, higher lattice enthalpy of Cs⁺

• Smaller hydration enthalpy of Li, higher lattice enthalpy of Cs⁺

• Smaller lattice enthalpy of Li, higher hydration enthalpy of Cs⁺

• Higher lattice enthalpy of Li, smaller hydration enthalpy of Cs⁺

The relative strength of trichlorides of boron group to accept a pair of electron is given by

• GaCl₃ > AlCl₃ > BCl₃

• AlCl₃ > BCl₃ > GaCl₃

• AlCl₃ > GaCl₃ > BCl₃

• BCl₃ > AlCl₃ > GaCl₃

If the ionic product of M (OH)₂ is 5 × 10^-10, then the molar solubility of M(OH)₂ in 0.1 M NaOH is

• 5 × 10^-12 M

• 5 × 10^-8 M

• 5 × 10^-10 M

• 5 × 10^-9 M

Equilibrium constants are given for the following two equilibria.

(i) A₂ (g) + B₂ (g) $\rightleftharpoons$ 2AB (g); K = 2 × 10^-4 L mol^-1

(ii) 2AB (g) + C₂ (g) $\rightleftharpoons$ 2ABC (g); K = 2 × 10^-2 L mol^-1

Calculate the equilibrium constant for the following equilibrium.

ABC (g) $\rightleftharpoons$ $\frac{1}{2}$A₂ (g) + $\frac{1}{2}$B₂ (g) + $\frac{1}{2}$C₂ (g)

• 500 mol^1/2 L^-1/2

• 500 mol^1/2 L^1/2

• 4 × 10^-6 mol^1/2 L^1/2

• 200 mol^1/2 L^-1/2

The equilibrium constant for the equilibrium PCl₅ (g) $\rightleftharpoons$ PCl₃ (g) + Cl₂ (g) at a particular temperature is 2 × 10^-2 mol L^-1. The number of moles of PCl₅ that must be taken in a one litre flask at the same temperature to obtain a concentration of 0.20 mole of chlorine at equilibrium is

• 2.2

• 2.0

• 1.8

• 0.2

The correct increasing order of the acid strength of benzoic acid (I), 4-nitrobenzoic acid (II), 3,4-dinitrobenzoic acid (III) and 4-methoxybenzoic acid (IV) is

• I < II < III < IV

• II < I < IV < III

• IV < I < II < III

• IV < II < I < III

Choose the correct order of decreasing basic strength of the following compounds in aqueous solution

(i) C₆H₅NH₂

(ii) C₂H₅NH₂

(iii) NH₃

(iv) (CH₃)₂NH

• (i) > (ii) > (iii) > (iv)

• (iv) > (ii) > (iii) > (i)

• (ii) > (i) > (iii) > (iv)

• (iv) > (iii) > (ii) > (i)

The salt of an alkali metal gives violet colour in the flame test. Its aqueous solution gives a white precipitate with barium chloride in hydrochloric acid medium. The salt is

• K₂SO₄

• KCl

• Na₂SO₄

• K₂CO₃

The values of limiting ionic conductance of H⁺ and HCOO^- ions are respectively 347 and 53S cm² mol^-1, the dissociation constant of methanoic acid at 298 K is

• 2.5 × 10^-4

• 2 × 10^-5

• 2.5 × 10^-5

• 1.5 × 10^-4

In a closed cylinder of capacity 24.6 L, the following reaction occurs at 27°C.

A₂ (s) $\rightleftharpoons$ B₂ (s) + 2C (g)

At equilibrium, 1 gm of B₂ (s) (molar mass = 50 g mol^-1) is present. The equilibrium constant K_p for the equilibrium in atm² unit is 

(R = 0.082 L atm K^-1 mol^-1)

• 1.6 × 10^-2

• 1.6 × 10^-5

• 1.6 × 10^-3

• 1.6 × 10^-4