Both of the following organic ions exist but one is MUCH more stable (A or B). Choose the correct claim(s), evidence(s), and reasoning(s).

a) Draw the ring-flip isomer of the molecule from question (b) Show which of the two is favored in the equilibrium between them, and explain why, showing all possible forms of strain in each of the isomers. (c） What is the stereochemical relationship between the two isomers? (d) Draw another stereoisomer of the molecule and show all the strains it contains.（strains is the most important one in this questuon！！！）

The structure shown below is has a very high pKa because the conjugate base is very unstable. Using the provided resonance structures, draw the curved electron-pushing arrows to show the deprotonation step. Then, draw the curved electron-pushing arrows to show the interconversion between resonance hybrid contributors. Be sure to account for all bond-breaking and bond-making steps. H Select to Add Arrows CH3CH2CH2CH2Li H Select to Edit Arrows H H LIⒸ

On the molecules on the back page, circle and label all of the functional groups that you see (identified in the table above). Please note the following tips that may help you on this assignment: If a molecule contains –COOH, or a C double bonded to an O and single-bonded to an –OH, the functional group you circle is only the carboxyl, not a carboxyl, carbonyl, and hydroxyl separately). Phosphate groups are tricky – any P surrounded by 4 O’s is a phosphate – adjacent phosphates may share an O, and sometimes the O is in the form of OH. There is often shorthand that is used in drawing these structures – if you see a jagged line or ring structure, assume that carbon is at each corner. There may be ionized forms of the functional groups above (such as NH2 or NH3+) – these are the same functional groups. The order of the atoms in the functional group may be switched, depending on which side of the molecule it is on. For example, “—NH3” and “H3N—“  are the same thing.