In: Chemistry
1. Write the balanced equation (not the mechanism) for the protonation of nitric acid by sulfuric acid, represented as an equilibrium expression.
2. Write the equilibrium constant expression for the reaction shown in question 1 above.
3. Consider the pKa values shown below:
H2SO4: -3
HSO4!: +2
HNO3: -1.3
H2NO3+: -13
Based on these pKa values, determine the equilibrium constant for the reaction that you wrote down for question 1.
4. The proton NMR spectrum of chlorobenzene was examined by Hiyamizu and coworkers in 1968. Their analysis revealed the following chemical shifts. The hydrogens ortho to the chlorine are at 7.28 ppm. The hydrogens meta to the chlorine are at 7.23 ppm. The hydrogen para to the chlorine is at 7.16 ppm.
A) Use arrow formalisms to draw resonance structures of chlorobenzene using the chlorine as an electron donor.
B) One might expect that the positions that have negative charges (and hence excess electron density) in the resonance structures would be the most upfield, but this is not the case. Explain why, and explain why the chemical shifts appear where they do relative to each other.