What is the name of the hybrid orbitals used by phosphorus in pcl3?

Which is mostly likely why many scientists reject the cold fusion theory

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.

What is the percentage of hydrogen in c2h4