The electrophile, E^⊕ attacks the benzene ring to generate the intermediate σ-complex. Of the following, which σ-complex is of lowest energy? 

Which one of the following is the correct statement?

• Boric acid is a protonic acid

• Beryllium exhibits coordination number of six

• Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase

• Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase

Amount of oxalic acid present in a solution can be determined by its titration with KMnO₄ solution in the presence of H₂SO₄. The titration gives unsatisfactory result when carried out in the presence of HCl, because HCl

• gets oxidised by oxalic acid to chlorine

• furnishes H+ions in addition to those from oxalic acid

• reduces permanganate to Mn²⁺

• reduces permanganate to Mn²⁺

In context with the industrial preparation of hydrogen from water gas (CO + H₂), which of the following is the correct statement?

• CO and H2 are fractionally separated using differences in their densities

• CO is removed by absorption in aqueous Cu2Cl2 solution

• H₂ is removed through occlusion with Pd

• H₂ is removed through occlusion with Pd

The correct decreasing order of priority for the functional groups of organic compounds in the IUPAC system of nomenclature is

• −COOH, −SO₃H, −CONH₂, −CHO

• −SO₃H, −COOH, −CONH₂, −CHO

• −CHO, −COOH, −SO₃H, −CONH₂

• −CHO, −COOH, −SO₃H, −CONH₂

16.

The coordination number and the oxidation state of the element ‘E’ in the complex [E(en)₂(C₂O₄)]NO2 (where(en) is ethylene diamine) are, respectively,

• 6 and 2

• 4 and 2

• 4 and 3

• 4 and 3

Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being

• 4f orbitals more diffused than the 5f orbitals

• lesser energy difference between 5f and 6d than between 4f and 5d orbitals

• more energy difference between 5f and 6d than between 4f and 5d orbitals

• more energy difference between 5f and 6d than between 4f and 5d orbitals

In which of the following octahedral complexes of Co (at. no. 27), will the magnitude of ∆o be the highest?

• [Co(CN)₆]³⁻

• [Co(C₂O₄)₃]³⁻

• [Co(H₂O)₆]³⁺

• [Co(H₂O)₆]³⁺

At 80^o C, the vapour pressure of pure liquid ‘A’ is 520 mm Hg and that of pure liquid ‘B’ is 1000 mm Hg. If a mixture solution of ‘A’ and ‘B’ boils at 80^o C and 1 atm pressure, the amount of ‘A’ in the mixture is (1 atm = 760 mm Hg)

• 52 mol percent

• 34 mol percent

• 48 mol percent

• 48 mol percent

For a reaction 1/2A →2B, rate of disappearance of ‘A’ is related to the rate of appearance of ‘B’ by the expression