Consider the nitrogen atoms (labeled A-D) in the molecule of 8-Chlorotheophyline shown below. Which of these nitrogen atoms do NOT possess a delocalized lone pair of electrons? O N =₁ B NEC D 8-Chlorotheophyline ܘ

The barrier to C-C bond rotation in ethanol (CH3-CH2-OH) is 14 kJ/mol. What energy can you assign to an H-O eclipsing interaction? Use strain energy increments from the table below in your calculation. (Specify units, kJ/mol; Calculate to nearest 0.1 energy units) Energy cost Interaction HH eclipsed H→ CH3 eclipsed Cause (kJ/mol) (kcal/mol) Torsional strain 4.0 1.0 Mostly torsional strain 6.0 1.4 CH3 -> CH3 eclipsed Torsional and steric strain 11.0 2.6 - CH3 CH3 gauche Steric strain 3.8 0.9

Compound A, C4H40, undergoes the ring substitution reactions characteristic of aromatics to give two isomers. Draw the structure of A. ring substitution 2 substitution isomers A Draw cations and anions in separate sketchers. • Separate structures with + signs from the drop-down menu. ChemDoodle

How r these two related?