11.

What is the conjugate base of OH^-?

• O₂

• H₂O

• O^-

• O^-

In which of the following arrangements the order is NOT according to the property indicated against it?

• Al³⁺ < Mg²⁺ < Na⁺ < F^- Increasing ionic size

• B < C < N < O Increasing first ionization enthalpy

• I < Br < F < Cl Increasing electron gain enthalpy (with negative sign)

• I < Br < F < Cl Increasing electron gain enthalpy (with negative sign)

Of the following sets which one does NOT contain isoelectronic species?

• PO^-3₄,SO₄^-2, ClO₄^-

• CN^-, N₂, C₂^-2

• SO₃^-2, CO₃^-2,NO₃^-

• SO₃^-2, CO₃^-2,NO₃^-

Among the following acids which has the lowest p_Ka value?

• CH₃COOH

• HCOOH

• (CH₃)₂COOH

• (CH₃)₂COOH

Which of the following statements in relation to the hydrogen atom is correct?

• 3s orbital is lower in energy than 3p orbital

• 3p orbital is lower in energy than 3d orbital

• 3s and 3p orbitals are of lower energy than 3d orbital

• 3s and 3p orbitals are of lower energy than 3d orbital

The structure of diborane (B₂H₆) contains

• four 2c-2e bonds and two 3c-2e bonds

• two 2c-2e bonds and four 3c-2e bonds

• two 2c-2e bonds and two 3c-3e bonds

• two 2c-2e bonds and two 3c-3e bonds

If the bond dissociation energies of XY, X₂ and Y₂ (all diatomic molecules) are in the ratio of 1:1:0.5 and ∆f H for the formation of XY is -200 kJ mole^-1. The bond dissociation energy of X₂ will be

• 100 kJ mol^-1

• 800 kJ mol^-1

• 300 kJ mol^-1

• 300 kJ mol^-1

Due to the presence of an unpaired electron, free radicals are:

• Chemically reactive

• Chemically inactive

• Anions

• Anions

The decreasing order of nucleophilicity among the nucleophiles

• (a), (b), (c), (d)

• (d), (c), (b), (a)

• (b), (c), (a), (d)

• (b), (c), (a), (d)

Of the five isomeric hexanes, the isomer which can give two monochlorinated compounds is

• n-hexane

• 2, 3-dimethylbutane

• 2,2-dimethylbutane

• 2,2-dimethylbutane