Chapter 12, Problem 12.105AP

a.

Interpretation Introduction

Interpretation:

For the lactic acid compound the chirality centers has to be labeled and number of chiral centers should be determined.

Concept introduction:

Chirality center:

When a carbon atom is bonded to four different groups, then that carbon is named as chiral carbon and it is called as chirality center. Generally, the carbon atom contains tetrahedral valency, therefore it bonded to four atoms or molecules. The chiral center is bonded with four different elements or groups. If the single carbon atom is bonded to two or more identical group or atom, then it is also not considered as chiral carbon. In addition to this, if the carbon atom contains multiple bond then it does not able to bond with four different groups then it is not considered to be as a chirality center.

b.

Interpretation Introduction

Interpretation:

For the lactic acid compound, Fischer projection formula has to be drawn.

Concept introduction:

Fischer projections:

In Fischer projection, the chirality center of the organic compounds are drawn using the following convention. First, the carbon atom is placed at the meeting point of the two lines of the cross. In a tetrahedron structure, the horizontal bonds indicate forward and denoted by wedges. The vertical bonds indicate backward and denoted by dashed lines. Finally, Fischer projection structure is abbreviated by cross formula.

Enantiomers:

Enantiomers are mirror image of one another and these are chiral molecules, but that are non superimposable on one another.