Please provide reasonable explanations why this can be the answer for this quest

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Please provide reasonable explanations why this can be the answer for this question

13. Consider the structure of the proton pump inhibitor (PPI) shown below. Functional groups 1 and 2 are weak bases with pKas listed in the structure. Select the TRUE statement. At pH 7.4, functional groups 1 and 2 will be highly unionized At pH 4, functional groups 1 and 2 will both be 50% ionized At pH = 1, functional group 1 will be ~ 50% unionized At pH = 1, functional group 2 will be approximately 90 ionized

Explanation / Answer

Nitrogen has lone pair

protonation means H+ ion accept electron from nitrogen

if nitrogen give electron it will get a positive charge that condition is ionic or ionized condition

here benzene ring you see, nitrogen is there which has pka 4

another side 5 membered ring you see there also nitrogen is there which has pKa 0.8

now pKa means -log Ka

Ka which means a measure of dissciation consant (acid dissociation constant) means N-H bond will break and N will like to be excist as unionized form

but pKa is -ve of log Ka

means pKa more means N will excist ans N-H or ionized form

so here pKa s are 0.8 and 4

so at below 0.8 and below 4 respective it will ionize or it will abstract H and excist as ionized form

now pH which is -log(concentration of H)

pH more means H will be less

pH 7.4 means H is less (water pH is 7)

in all other case in the option they have give pH is less means H is more

so we can tell at pH 7.4 where H is less there protonation or N-H bond will not form or N will not ionize

or N will excist as unionized form

hope you are able to under stand my explanation

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