This is because butterfly caterpillars are host specific. Plant-wise, the caterpillars of some butterfly species like asters, black-eyed Susan, clover, lupines, milkweed, sedum or violets. Aspen, birch, cherry, hackberry, oak or willow trees make caterpillars of other butterfly species equally happy.
each Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.ach Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.
No side of the molecule has more negative or positive charge than another side, and so the molecule is nonpolar: A water molecule is polar because (1) its O-H bonds are significantly polar, and (2) its bent geometry makes the distribution of those polar bonds asymmetrical.