2. An amino acid with three ionizable functional groups can exist in different forms and histidine is an example. [17 pts.] (a) Draw the structures of the predominant ionization state of histidine at pH 1, 4, 8 and 12. Include the net charge on the histidine molecule in each ionization state. (b) Write the equilibrium equations for the three ionizable protons present in histidine an assign the proper pKa for each ionization.

it is the most commonly accepted one

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l

answer; 4 electrons;

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.