Theories of acids and bases
3 marks · NormalIn the reaction: \[ HNO_3(aq) + NH_3(aq) \rightarrow NH_4^+(aq) + NO_3^-(aq) \] use the Bronsted-Lowry definition to identify:
The acid and the base on the left side of the equation. (1 mark)
The conjugate acid and conjugate base formed on the right side. (1 mark)
State which species donates the proton and which accepts it. (1 mark)
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Acid: HNO_3; Base: NH_3
(b) Conjugate acid: NH_4^+; Conjugate base: NO_3^-
(c) HNO_3 donates the proton; NH_3 accepts the proton.
Common mistakes: Confusing acid/base with conjugate acid/base; Mixing up donor and acceptor
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct identification of acid (HNO_3) and base (NH_3) on left side.
B2 (b) · 1 mark · Correct identification of conjugate acid (NH_4^+) and conjugate base (NO_3^-).
B3 (c) · 1 mark · States donor and acceptor: HNO_3 donates the proton to NH_3.
Worked solution
(a) HNO_3 is the acid because it donates a proton; NH_3 is the base because it accepts a proton.
(b) On the right, NH_4^+ is the conjugate acid (now has an extra H^+), and NO_3^- is the conjugate base (after HNO_3 loses a proton).
(c) HNO_3 donates the proton; NH_3 accepts the proton.