Question

give reasons why NH3 is polar while BF3 is not

Answer 1

as you can see the reason why nh3 is polar is because of this lone pair BH. ... but BH 3 is a nonpolar also if you were to draw the dipole moments for the bonds in ammonia. the nitrogen is much more electronegative than hydroge

Answer 2

in NH3 there is lonepair present on nitrogen and nitrogen have high electron negativity so dipole moment attract more towards nitrogen so it is polar