Q1-1-19P - Organic Chemistry (Mcmurry)

Question

The following model is a representation of citric acid, the key substance in the so-called citric acid cycle, by which food molecules are metabolized in the body. Only the connections between atoms are shown; multiple bonds are not indicated. Complete the structure by indicating the positions of multiple bonds and lone-pair electrons (gray 5 C, red 5 O, ivory 5 H).

Step-by-Step Solution

Answer

Ball and Stick Structure

Atoms and their non-bonded electrons

Citric acid

Citric acid contains seven oxygen atoms each of which has two lone pair electrons. Three of oxygen form a double bond with carbon. In the given structure gray balls represent carbons, red balls represent oxygen atoms and white balls represent hydrogen atoms.

Representation of ball and stick structure

Draw the atoms’  appropriate positions from the ball and stick structure. The ball and stick structure is represented as follows

Ball and stick structure

 

According to valence bond theory, every atom should satisfy the octane rule and the number of bonds present on atoms. The diagram showing atoms and their nonbonded electron is as shown

Atoms and their nonbonded electrons