Select the correct statements.

When lone pair of surrounding atom is involved in back bonding then bond angle does not change anywhere.

When lone pair of central atom is involved in back bonding then bond angle does not change.

In ${\mathrm{B}}_3{\mathrm{N}}_3{\mathrm{H}}_6$, all $\mathrm{B}-\mathrm{N}$ bond lengths are equal and these are shorter than the single $\mathrm{B}-\mathrm{N}$ covalent bonds due to delocalisation of ${\mathrm{\pi e}}^{-}$

${\mathrm{BF}}_3,{\mathrm{BCl}}_3$ are gaseous,${\mathrm{BBr}}_3$ liquid and ${\mathrm{BI}}_3$ solid because when size increases instantaneous dipole-induced dipole interaction increases.