Q: The nitrogen-containing reactant below (Reactant B) can act as a nucleophile in certain reactions. The reaction below is carried out in a pH = 4.5 buffer. This is because the pKa of the protonated carbonyl (Reactant A) is between -2 and -8, so there is a low concentration of this highly reactive electrophile at a pH of 4.5. If the pH is further lowered (from 4.5) in order to try and increase the concentration of this electrophile, which of the following correctly describes the likely counter-effect?
A		Increasing the acidity would cause less of Reactant B to become protonated (decreasing its nucleophilicity), and this would counteract the increase in electrophilicity of Reactant A.
B		Increasing the acidity would cause more of Reactant B to become protonated (decreasing its nucleophilicity), and this would counteract the increase in electrophilicity of Reactant A.
C		Increasing the acidity would cause more of Reactant B to become protonated and this would have no effect on the electrophilicity of Reactant A.
D		Increasing the acidity would have no effect on Reactant B and no effect on the electrophilicity of Reactant A.

Acid/Base Equilibria | Miscellaneous Organic Chemistry | Organic Chemistry Reactions | Molecular Structure |