each ionizable group of an amino acid can exist in one of two states, charged or neutral. the electric charge on the functional group is determined by the relationship between its pka and the ph of the solution. this relationship is described by the henderson–hasselbalch equation. histidine has three ionizable functional groups. complete the equilibrium equations by assigning the proper pka for each ionization and the net charge on the histidine molecule in each ionization state.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

i'm assuming that the correct answer is indeed the first one/ "a"..

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

answer: i dont know the answer but this might

explanation:

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