• In the reaction

$2 {X}+\mathrm{B}_2 \mathrm{H}_6 \rightarrow\left\lfloor\mathrm{BH}_2(\mathbf{X})_2\right\rfloor^{+}\left\lfloor\mathrm{BH}_4\right]^{-}$ the amine(s) ${X}$ is$(are)$

$(A)$ $\mathrm{NH}_3$ $(B)$ $\mathrm{CH}_3 \mathrm{NH}_2$ $(C)$ $\left(\mathrm{CH}_3\right)_2 \mathrm{NH}$ $(D)$ $\left(\mathrm{CH}_3\right)_3 \mathrm{~N}$

$H_3BO_3$ $\xrightarrow{{{T_1}}}X\xrightarrow{{{T_2}}}Y\xrightarrow{{red\,hot}}$ $B_2O_3$

if $T_1 < T_2$ then $X$ and $Y$ respectively are

Give oxidation state of gallium.

Which elements of group $13$ possess both $+1$ and $+3$ oxidation state? 

The compound($s$) which react($s$) with $NH _3$ to give boron nitride ($BN$) is(are)

$(A)$ $B$ $(B)$ $B _2 H _6$ $(C)$ $B _2 O _3$ $(D)$ $HBF _4$

Boron forms $BX_3$ type of halides. The correct increasing order of Lewis-acid strength of these halides is