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.
(b) P4 is non polar covalent. (c) BF3 is non polar covalent molecule (individual B-F bonds are polar but the net dipole moment is zero due to its triangular planar geometry).b) P4 is non polar covalent. (c) BF3 is non polar covalent molecule (individual B-F bonds are polar but the net dipole moment is zero due to its triangular planar geometry).