Hybridisation of boron in diborane is:

1.  $\mathrm{sp}$

2.  ${\mathrm{sp}}^2$

3.  ${\mathrm{sp}}^3$

4.  ${\mathrm{sp}}^3{\mathrm{d}}^2$

The blue coloured mineral 'Lapis Lazuli' used as semi precious stone is:

1.  sodium alumino silicate

2.  zinc cobaltate

3.  prussian blue

4.  basic copper carbonate

Red liquor is:

1.  ${\left({\mathrm{CH}}_3\mathrm{COO}\right)}_3<mspace\; width="1em"></mspace>\mathrm{Al}$

2.  $\mathrm{Al}{\left(\mathrm{OH}\right)}_3$

3.  ${\mathrm{Al}}_2{\left({\mathrm{CO}}_3\right)}_3$

4.  ${\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3$

Boron carbide, ${\mathrm{B}}_4\mathrm{C}$ is widely used for:

1.  making acetylene

2.  making plaster of Paris

3.  as a hardest substance after diamond

4.  making boric acid

Which one is explosive?

1.  ${\mathrm{PCl}}_5$

2.  $\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$

3.  ${\mathrm{NH}}_4{\mathrm{NO}}_3<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>\mathrm{Al}<mspace\; width="1em"></mspace>\mathrm{powder}$

4.  ${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NO}}_2$

${\mathrm{BCl}}_3$ does not exist as dimer but ${\mathrm{BH}}_3$ exist as dimer $\left({\mathrm{B}}_2{\mathrm{H}}_6\right)$ because:

1.chlorine is more electronegative than hydrogen

2.there is $\mathrm{p\pi }-\mathrm{p\pi }$ back bonding in ${\mathrm{BCl}}_3$ but ${\mathrm{BH}}_3$ does not contain such multiple bonding

3.large sized chlorine atoms do not fit in between the small boron atoms whereas small sized hydrogen atoms get fitted between boron atoms

4.none of the above

Which of the following imparts green colour to flame?

1.  $\mathrm{B}{\left(\mathrm{OMe}\right)}_3$

2.  $\mathrm{Na}\left(\mathrm{OMe}\right)$

3.  $\mathrm{Al}{\left({\mathrm{OBr}}_2\right)}_3$

4.  $\mathrm{Sn}{\left(\mathrm{OH}\right)}_2$

Borax bead test is responded by:

1.  Divalent metals

2.  Heavy metals

3.  Light metals

4.  Metal which forms coloured metaborates

Reactivity of borazole is greater than that of benzene because:

1.  borazole is non-polar compound

2.  borazole is polar compound

3.  borazole is electron deficient compound

4.  of localized electron in it

Inorganic benzene is:

1. $\mathrm{BN}$

2. ${\mathrm{BF}}_4$

3. ${\mathrm{B}}_2{\mathrm{H}}_6$

4. ${\mathrm{B}}_3{\mathrm{N}}_3{\mathrm{H}}_6$