Classifying Chemical Reactions

4.2 Classifying Chemical Reactions

1. Precipitation Reactions

This occurs when two soluble (dissolvable) solutions are mixed and form an insoluble solid called a precipitate. In clinical diagnostics, this principle is used to detect specific ions in urine or blood samples.

2. Acid-Base (Neutralization) Reactions

An acid reacts with a base to produce a salt and water.

Strong Acids/Bases: Dissociate (break apart) completely in water (e.g., HCl, NaOH).
Weak Acids/Bases: Only partially dissociate, often forming an equilibrium (e.g., vinegar or organic nitrogen compounds like "cadaverine").

✏️ Practice Problem: Identifying Spectator Ions
In the reaction AgNO₃(aq) + NaCl(aq) ➞ AgCl(s) + NaNO₃(aq), which ions are spectator ions (remain unchanged in the solution)? Click for Solution

Na⁺ and NO₃^- are spectator ions because they appear as (aq) on both sides.