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

473.

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

The pH of a saturated solution of a metal hydroxide of formula X(OH)₂ is 12.0 at 298 K. What is the solubility product of a metal hydroxide at 298 K (in mol³ L^-3)?

• 5 × 10^-7

• 2 × 10^-6

• 1 × 10^-7

• 5 × 10^-5

An inorganic salt (A) is decomposed on heating to give two products (B) and (C). Compound (C) is a liquid a room temperature and is neutral to litmus while the compound (B) is a colourless neutral gas. Compounds (A), (B) and (C) are 

• NH₄NO₃, N₂O, H₂O

• NH₄NO₂, NO, H₂O

• CaO, H₂O, CaCl₂

• Ba(NO₃)₂, H₂O, NO₂

The sum of pH and pK_b for a basic buffer solution is 13. The ratio of the concentration of the base to that of the salt is

• 10

• 1

• 0.05

• 0.1

Two equilibria, AB $\rightleftharpoons$ A +B. are simultaneously maintained in a solution with equilibrium constants, K₁ and K₂ respectively. The ratio of [A⁺] to [AB${}_2^{-}$] in the solution is

• directly proportional to [B^-]

• inversely proportional to [B^-]

• directly proportional to the square of [B^-]

• inversely proportional to the square of [B^-]