341.

Identify a species which is not a Bronsted acid but a Lewis acid

• BF₃

• H${}_3^{+}$O

• NH₃

• HCl

The pH of 10^-8 M HCl solution is

• 8

• 6.9586

• more than 8

• slightly more than 7

For the equilibrium,

CaCO₃ (s) $\rightleftharpoons$ CaO (s) + CO₂ (g) ; 

K_p = 1.64 atm at 1000 K

50 g of CaCO₃ in a 10 L closed vessel is heated to 1000 K. Percentage of CaCO₃ that remains unreacted at equilibrium is (Given, R = 0.082 L atm K^-1 mol^-1).

• 40

• 50

• 60

• 20

The acid strength of active methylene group in

I. CH₃COCH₂COOC₂H₅

II. CH₃COCH₂COCH₃

III. C₂H₅OOCCH₂COOC₂H₅

decreases as

• I > III > II

• I > II > III

• II > I > III

• III > I > II

A plot of $\frac{1}{T}$ vs k for a reaction gives the slope -1 × 10⁴ K. The energy of activation for the reaction is (Given, R = 8.314 K^-1 mol^-1)

• 8314 J mol^-1

• 1.202 kJ mol^-1

• 12.02 J mol^-1

• 83.14 kJ mol^-1

One mole of ammonia was completely absorbed in one litre solution each of

I. 1 M HCl

II. 1 M CH₃COOH 

III. 1 M H₂SO₄ at 298 K

The decreasing order for the pH of the resulting solution is (Given K_b (NH₃) = 4.74)

• II > III > I

• I > II > III

• II > I > III

• III > II > I

Conductivity of a saturated solution of a sparingly soluble salt AB at 298 K is 1.85 10^-6 Sm^-1. Solubility product of the salt AB at 298 K is

(Given, $\wedge {°}_{\mathrm{m}}$ (AB) = 140  Sm² mol^-1)

• 5.7 × 10^-12

• 1.32 × 10^-12

• 7.5 × 10^-12

• 1.74 

For the properties mentioned, the correct trend for the different species is in

• strength as Lewis acid - BCl₃ > AlCl₃ > GaCl₃

• inert pair effect - Al > Ga > ln

• oxidising property - Al³⁺ > ln³⁺ > Ti³⁺

• first ionization enthalpy - B > Al > Ti

In the reaction,

Fe(OH)₃ (s) $\rightleftharpoons$ Fe³⁺ (aq) + 3OH^- (aq), if the concentration of OH^- ions is decreased by $\frac{1}{4}$ times, then the equilibrium concentration of Fe³⁺ will increase by

• 8 times

• 16 times

• 64 times

• 4 times

Equilibrium constants K₁ and K₂ for the following equilibria,

I. NO (g) + $\frac{1}{2}$ O₂ (g) $\rightleftharpoons$ NO₂ (g)

II. 2NO₂ (g) $\rightleftharpoons$ 2NO (g) + O₂ (g) are related as

• K₁ = $\sqrt{{\mathrm{K}}_2}$

• K₂ = $\frac{1}{{\mathrm{K}}_1}$

• K₁ = 2K₂

• K₂ = $\frac{1}{{\mathrm{K}}_1^2}$