Q. The is a planar molecule whereas is pyramidal, because:

 2402  210 ManipalManipal 2004Chemical Bonding and Molecular Structure Report Error

Solution:

In boron trichloride, boron is hybridised and there is no lone pair on boron while in nitrogen. It is hybridised and there is a lone pair of electron in nitrogen. Hence, due to this reson is a planer molecule and is a pyramidal molecule.