1. Which of the following chemical equations represents a combustion reaction? A) NaCl + AgNO3 → AgCl + NaNO3 B) 2H2 + O2 → 2H2O C) Mg + 2HCl → MgCl2 + H2 D) FeCl3 + 3NaOH → Fe(OH)3 + 3NaCl Answer: B) 2H2 + O2 → 2H2O Rationale: In a combustion reaction, a substance reacts with oxygen to produce heat and light, typically forming water and carbon dioxide. 2. What is the balanced chemical equation for the reaction between potassium hydroxide (KOH) and hydrochloric acid (HCl)? A) KOH + Cl → KCl + H B) KOH + HCl → KCl + H2O C) KOH + HCl → KCl + HO D) KOH + HCl → KOCl + H2 Answer: B) KOH + HCl → KCl + H2O