Which reactants in the reactions below
are acting as Br©ªnsted-Lowry bases?
NH4
+(aq) + OH−(aq) <-> NH3(aq) + H2O(l)
H2PO4
−(aq) + H2O(l) <-> H3O+(aq) + HPO4
2−(aq)
is the answer H2O
and the H3O+
Both H2O and H3O^+ are products, not reactants. The question asks for the acid/base in the reactants. For whatever it is worth, H2O in equation 1 is acting as an acid because it is donating a H to NH3 to form NH4^+. In equation 2, H3O^+ is acting as an acid by donating a H to HPO4^-2. None of that answers your question but it may clarify it. What you want to do is to pick either NH4^+ or OH^- in equation 1 and determine which is the acid and which is the base. In equation 2 the choice is between H2PO4^- and H2O.
To determine which reactants are acting as Brønsted-Lowry bases in the given reactions, we need to understand the concept of Brønsted-Lowry acids and bases.
According to the Brønsted-Lowry acid-base theory, an acid is a species that donates a proton (H+ ion), while a base is a species that accepts a proton. In the given reactions:
1. NH₄⁺(aq) + OH⁻(aq) ⇌ NH₃(aq) + H₂O(l)
In this reaction, NH₄⁺ acts as an acid by donating a proton, while OH⁻ acts as a base by accepting the proton.
2. H₂PO₄⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HPO₄²⁻(aq)
In this reaction, H₂PO₄⁻ acts as an acid by donating a proton to water, and H₂O acts as a base by accepting the proton, forming H₃O⁺.
Therefore, in the first reaction, NH₄⁺ is the Brønsted-Lowry acid, and OH⁻ is the Brønsted-Lowry base. In the second reaction, H₂PO₄⁻ is the Brønsted-Lowry acid, and H₂O is the Brønsted-Lowry base.
So, in summary, in the given reactions, H₂O is acting as a base in the first reaction, and H₃O⁺ is acting as a base in the second reaction.