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

Why is CO₂ more effective than N₂ in extinguishing fires?

1. It is non-combustible.

2. It forms non-combustible products with burning substances.

3. It has a higher density than nitrogen.

4. It is chemically more reactive than nitrogen.

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

 Which among the following is a gas?

1. $B{F}_3$

2. $BC{l}_3$

3. $BB{r}_3$

4. $B{I}_3$

Which of the following products is formed when orthoboric acid is heated to red heat?

Which option correctly represents the two H–B–H bond angles found in diborane?

1. $60°,$ $120°$

2. $97°,120°$

3. $97°,150°$

4. $120°,$ $180°$

Which of the following carbides produces propyne on hydrolysis?

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.  ${\mathrm{SnH}}_4$

Which of the following represents the coordination number of Al in aluminate ions?