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.
The first one is polar bonds, which SiCl4 clearly has. The next is dissymmetry-in other words it can't be symmetrical. Because SiCl4 has a sp3 hybridization and is tetrahedral in shape, it is therefore symetrical and cannot be a polar molecule. Source(s): old chem notes.he first one is polar bonds, which SiCl4 clearly has. The next is dissymmetry-in other words it can't be symmetrical. Because SiCl4 has a sp3 hybridization and is tetrahedral in shape, it is therefore symetrical and cannot be a polar molecule. Source(s): old chem notes.