Acid-Base Reactions in GOB Chemistry: Types, Equations, and Practice

Acid-Base Reactions

Overview of Acid-Base Reactions

Acid-base reactions are fundamental in general, organic, and biological (GOB) chemistry. These reactions involve the transfer of protons (H+) between acids and bases, and can occur with a variety of reactants including hydroxide bases, neutral amines, metals, and metal oxides.

• Acids: Substances that donate protons (H+).

• Bases: Substances that accept protons. Common bases include hydroxide ions (OH-), neutral amines, and metal oxides.

• Amines: Compounds containing nitrogen (N) bonded to hydrogen (H) or alkyl groups. Neutral amines are typically weak bases.

Types of Acid-Base Reactions

Acid-base reactions can be classified based on the type of base involved. The following table summarizes the main types:

Type of Reaction	General Equation	Example
Acid reacts with Hydroxide Base	$\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water}$	$\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}$
Acid reacts with Neutral Amine	$\text{Acid} + \text{Amine} \rightarrow \text{Ammonium Salt}$	$\text{HCl} + \text{NH}_3 \rightarrow \text{NH}_4\text{Cl}$
Acid reacts with Metal	$\text{Acid} + \text{Metal} \rightarrow \text{Salt} + \text{Hydrogen Gas}$	$2\text{HCl} + \text{Zn} \rightarrow \text{ZnCl}_2 + \text{H}_2$
Acid reacts with Metal Oxide	$\text{Acid} + \text{Metal Oxide} \rightarrow \text{Salt} + \text{Water}$	$2\text{HCl} + \text{FeO} \rightarrow \text{FeCl}_2 + \text{H}_2\text{O}$

Key Terms and Definitions

• Salt: An ionic compound formed from the neutralization of an acid and a base.

• Neutralization: The reaction between an acid and a base to produce a salt and water.

• Ammonium Salt: A salt formed when an acid reacts with an amine, resulting in a positively charged ammonium ion.

Examples of Acid-Base Reactions

• Hydrochloric acid and sodium hydroxide: $\text{HCl} (aq) + \text{NaOH} (aq) \rightarrow \text{NaCl} (aq) + \text{H}_2\text{O} (l)$

• Hydrofluoric acid and potassium hydroxide: $\text{HF} (aq) + \text{KOH} (aq) \rightarrow \text{H}_2\text{O} (l) + \text{KF} (aq)$

• Hydrochloric acid and ammonia: $\text{HCl} (aq) + \text{NH}_3 (aq) \rightarrow \text{NH}_4\text{Cl} (aq)$

• Hydrochloric acid and zinc metal: $2\text{HCl} (aq) + \text{Zn} (s) \rightarrow \text{ZnCl}_2 (aq) + \text{H}_2 (g)$

• Hydrochloric acid and iron(II) oxide: $2\text{HCl} (aq) + \text{FeO} (s) \rightarrow \text{FeCl}_2 (aq) + \text{H}_2\text{O} (l)$

Practice Problems

• Write a balanced chemical equation for bromic acid reacting with hydrazine (NH2NH2): $\text{HBrO}_3 (aq) + \text{NH}_2\text{NH}_2 (aq) \rightarrow \text{NH}_2\text{NH}_3^+ (aq) + \text{BrO}_3^- (aq)$ Additional info: The product is an ammonium ion and a bromate ion.

• Write a balanced chemical equation, including phases, for HClO2 reacting with Zn metal: $2\text{HClO}_2 (aq) + \text{Zn} (s) \rightarrow \text{Zn(ClO}_2)_2 (aq) + \text{H}_2 (g)$ Additional info: The reaction produces zinc chlorite and hydrogen gas.

• Write a balanced chemical equation, including phases, for HBr reacting with Li2O: $2\text{HBr} (aq) + \text{Li}_2\text{O} (s) \rightarrow 2\text{LiBr} (aq) + \text{H}_2\text{O} (l)$

Summary Table: Types of Acid-Base Reactions

Acid	Base	Products	Example Equation
HCl	NaOH	NaCl, H2O	$\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}$
HCl	NH3	NH4Cl	$\text{HCl} + \text{NH}_3 \rightarrow \text{NH}_4\text{Cl}$
HCl	Zn	ZnCl2, H2	$2\text{HCl} + \text{Zn} \rightarrow \text{ZnCl}_2 + \text{H}_2$
HCl	FeO	FeCl2, H2O	$2\text{HCl} + \text{FeO} \rightarrow \text{FeCl}_2 + \text{H}_2\text{O}$

Additional info:

• Neutral amines are weak bases and react with acids to form ammonium salts.

• Metal oxides act as bases and react with acids to form salts and water.

• Practice problems reinforce the ability to write and balance chemical equations, including correct phase notation.