1. Conjugate acids and conjugate bases come from the Bronsted-Lowry Theory which states:All acids are proton H+ donors, and also all bases are proton H+ acceptors.2. A conjugate acid is the base after itreceives the proton, and also a conjugate base is the acid after it loses the proton.I recognize it"s still a tiny bit confutilizing, so let"s look at these examples toclarify everything:Example #1-1a. First, let"s figure out what is the proton donor and what is the proton acceptor.*In this reaction, our acid (HCl) is a monoprotic acid because it has one H+ ion. HCl + NH3 -> NH4+ + Cl- Acid/ Base/ + because it - bereason it Proton Donor Proton Acceptor gains an H+ ion loses an H+ ion*The shade represents wbelow the H+ ion isbeing displacedto.1b. Now, let"s usage that very same example to present which is the conjugate acid and also which is the conjugate base: HCl + NH3 -> NH4+ + Cl- Acid Base Conjugate Acid Conjugate Base*The molecule from the HCl (acid) is "donating" itself to NH3(base). Cl- is the conjugate base bereason it looses an H+ molecule, and also NH4+ is the conjugate acid because it is "accepting" the H+ that was "donated" by the HCl.Here is a photo of example #1-

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Hopefully we"re expertise this topic a little little bit better, so let"s carry out one more example:Example #2-2a. Just like the first instance, let"s number out which one is the proton acceptor andwhich one is the proton donor.*In this reactivity, our acid (H2O) is adiuretic acid bereason it has actually two H+ ions. H2O + NH3 -> NH4+ + OH- Acid/ Base/ + because it - because it Proton Donor Proton Acceptor gains an H+ ion loses an H+ ion*Before we relocate on I want to answer a question that I know you have:How is H2O the acid/proton donor if H2O has actually a pH of 7 and also is neutral (neither an acid or base)?Although that is true, H2O is a proton donor,classifying it as an acid under the Bronsted-Lowry Theory.

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When it "donates" a H+ ion, it becomes a conjugate base because it is offering ameans a H+ ion.2b. Now that we understand which is our proton donor and also which is our proton acceptor, let"s select our conjugate acid and our conjugate base: H2O + NH3 -> NH4+ + OH- Acid Base Conjugate Acid Conjugate BaseHere is a picture of instance #2: