H2: non polar bond. non polar molecule
H2O: polar bonds, but there is a angle between 2 H-O bonds. so it's a polar molecule
NH3: polar bonds, but it's a stereochemical structure, like a pyramid with triangle base, N is the vertex. polar molecule.
NaCl: polar bond, polar molecule.(ion bond)
CO2: 2 O atoms are at two sides of C atom horizonally. giving CO2 a symmerical structure. it's nonpolar molecule with 2 polar bonds.
