3. In Technique 3, the filtrate can be treated with HCl to a pH of 2.0 to crystallize the N-acetyl-D-isoleucine. This can be hydrolyzed to the amino acid in 1.0 M HCl. The D enantiomer can be treated with racemase to generate a D-L mixture again. Technique 3  can be applied to this mixture once again to isolate more L enantiomer. Why will this process become futile after three cycles?
   
   
   1. The percent of the enantiomer obtained from the third cycle is only 12.5% of the product mixture.
   2. The percent of the enantiomer obtained from the third cycle is only 6.25% of the product mixture.
   3. Hog renal acylase is consummed completely by the third cycle.
   4. The acetic anhydride reacts only when the mixture has a substantial amount of L-enatiomer.