In this reaction, NH4+ + H2O -> H3O+ + NH3 the conjugate base of H3O+ ion is:
Correct answer: B. H2O
- A. NH4+
- B. H2O
- C. H+
- D. NH3
Explanation
A conjugate acid, within the Brønsted-Lowry acid-base theory, is a chemical compound formed when an acid donates a proton to a base-in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a hydrogen ion. Hence, Option B (H2O) is correct while other options are rendered as incorrect.
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About Bronsted-Lowry and Lewis Concepts
The Brønsted-Lowry concept defines acids as proton donors and bases as proton acceptors, producing conjugate acid-base pairs. The Lewis concept extends the idea to electron-pair acceptors and donors, so compounds such as BF3 and NH3 can be treated as acid and base even without proton transfer, unlike the Arrhenius definition.
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