11.

Activation energy (E_a) and rate constants (k₁ and k₂) of chemical reaction at two different temperatures (T₁ and T₂) are related by

• 
• 
• 
• 

Standard reduction potentials of the half-reactions are given below.

F₂ (g) +2e^- → 2F^- (aq) ;  E^o = +2.85 V
Cl₂ (g) +2e^- →2Cl^- (aq) ; E^o = +1.36V
Br₂ (l) +2e^- → 2Br^- (aq) ; E^o = +1.06 V
I₂ (s) +2e^- →2I^- (aq); E^o = +0.53 V

The strongest oxidising and reducing agents respectively are

• F₂ and I^-

• Br₂ and Cl^-

• Cl₂ and Br^-

• Cl₂ and Br^-

Vapour pressure of chloroform (CHCl₃) and dichloromethane (CH₂Cl₂) at 25^oC are 200 mmHg and 41.5 mmHg respectively, Vapour pressure of the solution obtained by mixing 25.5 g of CHCl₃ and 40 g of CH₂Cl₂ at the same temperature will be
(molecular mass of CHCl₃= 119.5 u and molecular mass of CH₂Cl₂ = 85 u)

• 173.9 mmHg

• 615.0 mmHg

• 347.9 mmHg

• 347.9 mmHg

Molar conductivities (Λ^o_m) at infinite dilution of NaCl, HCl and CH₃COONa are 126.4, 425.9 and 91.0 S Cm² mol^-1 respectively. Λ^o_m for CH₃COOH will be

• 425.5 S cm² mol^-1

• 180.5 S cm² mol^-1

• 290.8 S cm² mol^-1

• 290.8 S cm² mol^-1

Which one of the following does not correctly represent the correct order of the property indicated aginst it? 

• Ti < V<Cr< Mn: increasing number of oxidation states

• Ti< V<Cr³⁺<Mn³⁺ : increasing magnetic moment

• Ti < V < Cr < Mn : Increasing melting points

• Ti < V < Cr < Mn : Increasing melting points

Four successive members of the first series of the transition metals are listed below. For which one of them, the standard potential value has a positive sign?

• Co (Z=27)

• Ni (Z=28)

• Cu (Z=29)

• Cu (Z=29)

In Which of the following arrangement, the given sequence is not strictly according to the property indicated against it ? 

• HF < HCl< HBr < HI : increasing acidic strength

• H₂O < H₂S < H₂Se < H₂Te : increasing pK_a values.

• NH₃ < PH₃ < AsH₃ < SbH₃  : increasing acidic character

• NH₃ < PH₃ < AsH₃ < SbH₃  : increasing acidic character

The catalytic activity of transition metals and their compounds is ascribed mainly to

• their magnetic behaviour

• their unfilled d- orbitals

• their ability to adopt variable oxidation states

• their ability to adopt variable oxidation states

Which of the following exhibits only +3 oxidation states?

• U

• Th

• Ac

• Ac

The Gibb's energy for the decomposition of Al₂O₃ at 500^o C is as follow
2/3 Al₂O₃ → 4/3 Al + O₂;
Δ_rG = +960 kJ mol^-1
The potential difference needed for the electrolytic reduction aluminium oxide (Al₂O₃) at 500⁰ C is at least 

• 4.5 V

• 3.0 V

• 2.5 V

• 2.5 V