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

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

In the structure of diborane,

A compound X, of boron, reacts with NH₃ on heating to give another compound Y which is called inorganic benzene. The compound X can be prepared by treating BF₃ with lithium aluminum hydride. The compounds X and Y are represented by the formulas.

1.  B₂H₆, B₃N₃H₆

2.  B₂O₃, B₃N₃H₆

3.  BF₃, B₃N₃H₆

4.  B₃N₃H₆, B₂H₆

Quartz is extensively used as a piezoelectric material, it contains-

Dry ice is:

The reason for the small radius of Ga compared to Al is-.

a.  Poor screening effect of d and f orbitals

b.  Increase in nuclear charge

c.  Presence of higher orbitals

d.  Higher atomic number

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

The linear shape of CO₂ is due to:

a.  sp³ hybridisation of carbon

b.  sp hybridisation of carbon

c.  $\mathrm{p\pi }-\mathrm{p\pi }$ bonding between carbon and oxygen

d.  sp² hybridisation of carbon

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)