Percent yield & Limiting reagent

Question

If a students adds three times as much phenanthroline than she was supposed to when attempting the red crystal synthesis how does this effect the actual, theoretical and percent yield?

Answer 1

I'm assuming you're referring to Phenanthroline complexes of Grignard or lithium reagents. Assuming you are able to dissolve all of the phenanthroline in solution, your actual yield will go down because your solution will contain excess phenanthroline, which will interfere with crystal formation.

 

The theoretical yield should remain unchanged because the Grignard will be the limiting reagent.

 

The percent yield will go down because your actual yield will decrease.