Which among the following is a gas?

1. $B{F}_3$

2. $BC{l}_3$

3. $BB{r}_3$

4. $B{I}_3$

What happens when aluminium is added to an aqueous potassium hydroxide solution?

1. No reaction takes place 

2. Oxygen gas is evolved

3. Water is produced 

4. Hydrogen gas is evolved

CO₂ and N₂ are non-supporters of combustion. However, for putting out fires CO₂ is preferred over N₂ because CO₂:

1. Does not burn.

2. Forms non-combustible products with burning substances.

3. Is denser than nitrogen.

4. Is a more reactive gas.

Find the amphoteric oxide among the following.

Aluminium chloride in acidified aqueous solution forms a complex 'A'.
The formula of A and hybridisation state of Al in 'A' is respectively:

1. [Al(H₂O)₆]³⁺, sp³d²

2. [Al(H₂O)₄]³⁺, sp³

3. [Al(H2O)4]3+, dsp2

4. [Al(H₂O)]³⁺, d²sp³

Orthoboric acid when heated to red hot gives-

In diborane, the two H-B-H angles are nearly-

1. $60°,$ $120°$

2. $97°,120°$

3. $97°,150°$

4. $120°,$ $180°$

A compound that gives propyne on hydrolysis is -

1. ${\mathrm{Al}}_4{\mathrm{C}}_3$

2. ${\mathrm{Mg}}_2{\mathrm{C}}_3$

3. ${\mathrm{B}}_4\mathrm{C}$

4. ${\mathrm{La}}_4{\mathrm{C}}_3$

Find the most volatile compound among the following.

1.  ${\mathrm{CH}}_4$

2.  ${\mathrm{SiH}}_4$

3.  ${\mathrm{GeH}}_4$

4.  ${\mathrm{SnH}}_4$

The coordination number of Al in aluminates, is: