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

Diborane does not undergo cleavage reaction with:

1.  trimethyl amine

2.  ammonia

3.  $\mathrm{CO}$

4.  ${\mathrm{CO}}_2$

Fluorine is more electronegative than either boron or phosphorus. What conclusion can be drawn from the fact that ${\mathrm{BF}}_3$ has no dipole moment but ${\mathrm{PF}}_3$ has?

1.  ${\mathrm{BF}}_3$ is spherically symmetrical, ${\mathrm{PF}}_3$ is not

2.  ${\mathrm{BF}}_3$ molecule must be linear

3.  The atomic radius of P is larger than the atomic radius of B

4.  The ${\mathrm{BF}}_3$ molecule must be planar triangular

Borazine is obtained by reaction of:

1.  ${\mathrm{NH}}_3+{\mathrm{B}}_2{\mathrm{H}}_6 \mathrm{in} 2 : 1 \mathrm{ratio}$

2.  ${\mathrm{NH}}_3+{\mathrm{B}}_2{\mathrm{H}}_6 \mathrm{in} 1 : 2 \mathrm{ratio}$

3.  ${\mathrm{NH}}_3+{\mathrm{B}}_2{\mathrm{H}}_6 \mathrm{in} 1 : 4 \mathrm{ratio}$

4.  ${\mathrm{NH}}_3+{\mathrm{B}}_2{\mathrm{H}}_6 \mathrm{in} 4 : 1 \mathrm{ratio}$

Boric acid is not used:

1. As an antiseptic

2. As a flux in soldering

3. In making optical glasses

4. In making enamels and pottery glazes

An incorrect statement among the following regarding Al₂Cl₆ is: