Properties of Ammonia and Ammonium Ion

Steps:

• Statement 1: In water, NH₃ accepts H⁺ from H₂O to form NH₄⁺ and OH⁻; no coordinate bond forms between NH₃ and OH⁻, as NH₃ donates lone pair to H⁺, not OH⁻.
• Statement 2: NH₄⁺ donates H⁺ (e.g., NH₄⁺ + OH⁻ → NH₃ + H₂O), qualifying as Brønsted-Lowry acid by proton donation.
• Statement 3: NH₃ has trigonal pyramidal shape with H-N-H angle ~107° due to lone pair repulsion; NH₄⁺ is tetrahedral with ~109.5° angle, so larger.
• Statements 2 and 3 hold, while 1 does not, selecting option C.

Why C is correct:

• Matches Brønsted-Lowry definition (proton donor for NH₄⁺) and VSEPR theory (geometry predicts larger angle in NH₄⁺).

Why the others are wrong:

• A: Includes false statement 1.
• B: Includes false statement 1, excludes correct statement 2.
• D: Includes false statement 1.

Final answer: C