What mass of pcl5 will be produced from the given masses of both reactants? 27 60?

2P = 62g needs 5Cl2 = 355g Cl2 to react; so 28g P needs 355/62 x 28g Cl2 = 160.32g , so you don't have adequate chlorine so chlorine is the limiting reagent,. 
from the equation 355g Cl2 stretches 479gg PCl5 ; so 54g Cl2 gives 479/355 x 54 = 72.86g

d: the voltage of the secondary coil is less than that of the primary coil.

im not suree sorry if wrong

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.