An aqueous solution is disclosed including water, an acid, a nitrogen-containing compound, and a functionalizing agent (FA), which can be a ketone, diketone, aldehyde, dialdehyde, organic acid, and combinations thereof. An additional aqueous solution is disclosed including water, an acid, and an acid neutralizing agent which can be a reaction product of at least a portion of the nitrogen-containing compound and the functionalizing agent. Methods of treating a formation are also disclosed including treating a formation fluidly coupled to a wellbore with an oilfield treatment fluid comprising either or both of the aqueous solutions.