Which of the following is a polar molecule?

For which of the following molecules, significant $\mathrm{\mu }\ne 0$?

Among the following species, identify the isostructural pairs

${\mathrm{NF}}_3 , {{\mathrm{NO}}_3}^{-}, {\mathrm{BF}}_3 , {\mathrm{H}}_3{\mathrm{O}}^{+} , {\mathrm{HN}}_3$

The correct order of hybridisation of the central atom in the following species

${\mathrm{NH}}_3, {[{\mathrm{PtCl}}_4{]}_2}^{-}, {\mathrm{PCl}}_5$and ${\mathrm{BCl}}_3$is