Which of the following is a Lewis acid?

1. ${\mathrm{AlCl}}_3$

2. ${\mathrm{MgCl}}_2$

3. ${\mathrm{CaCl}}_2$

4. ${\mathrm{BaCl}}_2$

The geometry of a complex species can be understood from the knowledge of the type of hybridization of orbitals of the central atom. The hybridization of orbitals of a central atom in ${\left[\mathrm{B}\right({\mathrm{OH}}_4\left)\right]}^{-}$ and the geometry of the complex are respectively

Which of the following oxides is acidic in nature?

1. ${\mathrm{B}}_2{\mathrm{O}}_3$

2. ${\mathrm{Al}}_2{\mathrm{O}}_3$

3. ${\mathrm{Ga}}_2{\mathrm{O}}_3$

4. ${\mathrm{In}}_2{\mathrm{O}}_3$

The exhibition of the highest coordination number depends on the availability of vacant orbitals in the central atom. Which of the following elements is not likely to act as a central atom in ${\mathrm{MF}}_6^{3-}$?

1. B

2. Al

3. Ga

4. In

Boric acid is an acid because its molecule

1. Contains replaceable H⁺ ion

2. Gives up a proton

3. Accepts OH^- from water releasing proton

4. Combines with proton from water molecule

The correct increasing order of tendency for catenation among group 14 elements?

1.  $\mathrm{C}>\mathrm{Si}>\mathrm{Ge}>\mathrm{Sn}$

2.  $\mathrm{C}>>\mathrm{Si}>\mathrm{Ge}\approx \mathrm{Sn}$

3.  $\mathrm{Si}>\mathrm{C}>\mathrm{Sn}>\mathrm{Ge}$

4.  $\mathrm{Ge}>\mathrm{Sn}>\mathrm{Si}>\mathrm{C}$

Silicon has a strong tendency to form polymers like silicones. The chain length of silicone polymer can be controlled by adding

The correct order of Ionization enthalpy (∆_iH kJ mol^–1)  for the elements of group 13 among the following is:

1. B > Al > Ga > In > Tl

2. B < Al < Ga < In < Tl

3. B < Al > Ga < In < Tl

4. B > Al < Ga > In < Tl

In the structure of diborane,

Identify more than one correct resonance structures of carbon dioxide from the ones given below:

a.  ${}^{-}\mathrm{O}-\mathrm{C}={\mathrm{O}}^{+}$

b.  $\mathrm{O}=\mathrm{C}=\mathrm{O}$

c.  ${}^{-}\mathrm{O}\equiv \mathrm{C}-{\mathrm{O}}^{+}$

d.  ${}^{-}\mathrm{O}-\mathrm{C}\equiv {\mathrm{O}}^{+}$

Choose the correct option: