Explain why if benzoic acid were substituted for 2-methoxyphenylacetic acid in this experiment the enantiomeric ratio of the yeast reduction product...

Explain why if benzoic acid were substituted for 2-methoxyphenylacetic acid in this experiment the enantiomeric ratio of the yeast reduction product could not be determined by 1 H NMR. If you begin with 50 mmol of benzaldehyde, and all 4 steps in your synthesis proceed in 100% yield and you were to use all of the product of each step in the next, what would be the yield of final product in grams? What if each step proceeds in 75% yield?