In which of the following molecules/ions BF₃, ${\mathrm{NO}}_2^{-}$, ${\mathrm{NH}}_2^{-}$ and H₂O, the central atom is sp² hybridised?

1. ${\mathrm{NO}}_2^{-}$ and ${\mathrm{NH}}_2^{-}$
2. ${\mathrm{NH}}_2^{-}$ and H₂O
3. ${\mathrm{NO}}_2^{-}$ and H₂O
4. BF₃, and ${\mathrm{NO}}_2^{-}$

What is the dominant intermolecular force on bond that must be overcome in converting

liquid CH₃OH to a gas?

1. Hydrogen bonding

2. Dipole-dipole interaction

3. Covalent bonds

4. London dispersion force

The correct order of increasing bond angles in the following triatomic species is

(1) NO₂^- < NO₂⁺ < NO₂

(2) NO₂^- < NO₂   < NO₂⁺

(3) NO₂⁺ < NO₂   <NO₂^-

(4) NO₂⁺ < NO₂^- < NO₂

In the hydrocarbon

     CH₃-CH=CH-CH₂-C$\equiv$CH

     6      5     4   3      2    1

The state of hybridisation of carbons 1,3 and 5 are in the following sequence

(1) sp², sp, sp³                       

(2) sp, sp³, sp²

(3) sp, sp², sp³                       

(4) sp³, sp², sp

The correct order of increasing thermal stability of K₂CO₃, MgCO₃, CaCO₃ and BeCO₃ is:
(1) BeCO₃ < MgCO₃ < K₂CO₃ < CaCO₃

(2) BeCO₃ < MgCO₃ < CaCO₃ < K₂CO₃

(3) MgCO₃ < BeCO₃ < CaCO₃ < K₂CO₃

(4) K₂CO₃ < MgCO₃ < CaCO₃ < BeCO₃

Which of the following compounds has a higher hydration energy than the lattice energy?

1. BaSO₄                           

2. MgSO₄

3. CaSO₄                           

4. SrSO₄

The correct order of electronegativity of hybrid orbitals of carbon is:

(1) sp>sp²<sp³             

(2) sp>sp²>sp³

(3) sp<sp²>sp³             

(4) sp<sp²<sp³

Which of the following is the most basic oxide?
(1) Al₂O₃

(2) Sb₂O₃

(3) Bi₂O₃

(4) SeO₂

The number of unpaired electrons in a paramagnetic diatomic molecule of an element with atomic mass 16 is :

1. 2

2. 3

3. 4

4. 1

Which of the following is not isostructural with SiCl₄?

(a) SCl₄            (b) ${\mathrm{SO}}_4^{2-}$               (c) ${\mathrm{PO}}_4^{3-}$                 (d) ${\mathrm{NH}}_4^{+}$