The molar mass of l2 is 253.80g/mol and the molar mass of nl3 is the 394.71g/mol. how many moles of l2 will form 38.58 g of ni3

The  moles   of I2  that will   form  38.58g  of Ni3  is  0.147 moles

   calculation
write the  equation  for  reaction  for  formation of   Ni3 from I2  and N2

that is   3I2 +  N2  = 2NI3
 
find the moles  of  Ni3  formed   =  mass/molar mass

=   38.58g/ 394.71  g/mol  = 0.098  moles

by use  of  mole ratio  between  I2  to NI3  which is  3 :2 the  moles of  I2

=  0.098  x3/2 =  0.147  moles

Coal i believe hope this