Oxide Reactions: Videos & Practice Problems

Oxides, peroxides, and superoxides from groups 1A and 2A are reactive compounds that can interact with water to form hydroxides, which are basic, or with acids to yield salts and water. For example, lithium oxide reacts with water to produce lithium hydroxide, while calcium oxide reacts with hydrochloric acid to form calcium chloride and water. This highlights the importance of understanding acid-base reactions and the formation of ionic compounds in chemical processes.

Oxide Reactions

Oxides, peroxides, and superoxides from groups 1A and 2A are known for their reactivity, particularly in their interactions with water and acids. When these compounds react with water, they form hydroxides, which are basic in nature. For example, when lithium oxide (Li₂O) reacts with water (H₂O), it produces lithium hydroxide (LiOH), a strong base. The balanced chemical equation for this reaction is:

Li₂O + 2 H₂O → 2 LiOH

In addition to reacting with water, these oxides can also react with acids to produce salts and water. For instance, when calcium oxide (CaO) reacts with hydrochloric acid (HCl), it forms calcium chloride (CaCl₂) and water. The balanced equation for this reaction is:

CaO + 2 HCl → CaCl₂ + H₂O

In summary, the key reactions involving oxides include their ability to produce bases when reacting with water and to form salts and water when reacting with acids. Understanding these reactions is essential for grasping the behavior of these reactive compounds in various chemical contexts.

Oxide Reactions Example

In the reaction between lithium oxide and hydrochloric acid, we observe the formation of water and a salt. Lithium oxide (Li₂O) consists of lithium ions (Li⁺) and oxide ions (O^2-), while hydrochloric acid (HCl) is composed of hydrogen ions (H⁺) and chloride ions (Cl^-). When these react, the lithium ions combine with chloride ions to form lithium chloride (LiCl), which is aqueous, and the oxide ions react with hydrogen ions to produce water (H₂O).

To balance the chemical equation, we start with the unbalanced reaction:

Li₂O (s) + HCl (aq) → LiCl (aq) + H₂O (l)

To ensure that the number of atoms for each element is equal on both sides, we place a coefficient of 2 in front of HCl and LiCl:

Li₂O (s) + 2 HCl (aq) → 2 LiCl (aq) + H₂O (l)

This balanced equation now accurately represents the stoichiometry of the reaction, with 2 lithium atoms and 2 chlorine atoms on both sides, along with the formation of one molecule of water.

Write a balanced equation to show what happens when strontium oxide dissolves in water.

• A. Sr₂O₃(s) + 3 H₂O(l) → 2 Sr(OH)₃(aq)
• B. SrO(s) + H₂O(l) → Sr(OH)₂(aq)
• C. SrO₂(s) + 2 H₂O(l) → Sr(OH)₄(aq)
• D. Sr₂O(s) + H₂O(l) → 2 SrOH(aq)

Answer: (B)

Write a balanced equation for the reaction of magnesium oxide with aqueous hydrochloric acid.

• A. MgO(s) + HCl(aq) → MgCl(aq) + OH(aq)
• B. MgO₂(s) + 4 HCl(aq) → MgCl₄(aq) + 2 H₂O(l)
• C. MgO(s) + 2 HCl(aq) → MgCl₂(aq) + H₂O(l)
• D. Mg₂O(s) + 2 HCl(aq) → 2 MgCl(aq) + OH(aq)

Answer: (C)

Here’s what students ask on this topic:

What are the reactions of oxides with water?

Oxides, particularly those of groups 1a and 2a, react with water to form hydroxides, which are basic in nature. For example, lithium oxide (Li₂O) reacts with water (H₂O) to produce lithium hydroxide (LiOH). The balanced chemical equation for this reaction is:

${\mathrm{Li}}_2+H_{2}O\to {\mathrm{Li}}_2\left({\mathrm{OH}}_2\right)$

This reaction produces a basic solution due to the formation of hydroxide ions (OH^-).

How do oxides react with acids?

Oxides react with acids to produce salts and water. For example, calcium oxide (CaO) reacts with hydrochloric acid (HCl) to form calcium chloride (CaCl₂) and water (H₂O). The balanced chemical equation for this reaction is:

${\mathrm{CaO}}_{+}$

This reaction produces a salt (calcium chloride) and water.

What is the difference between oxides, peroxides, and superoxides?

Oxides, peroxides, and superoxides are compounds that contain oxygen but differ in their oxygen content and bonding. Oxides contain the O^2- ion, such as in Li₂O. Peroxides contain the O₂^2- ion, such as in H₂O₂. Superoxides contain the O₂^- ion, such as in KO₂. These differences affect their reactivity and the types of reactions they undergo.

Why do oxides of groups 1a and 2a form basic solutions when reacting with water?

Oxides of groups 1a and 2a form basic solutions when reacting with water because they produce hydroxide ions (OH^-). For example, when lithium oxide (Li₂O) reacts with water, it forms lithium hydroxide (LiOH), which dissociates in water to release OH^- ions. These hydroxide ions increase the pH of the solution, making it basic. The general reaction can be represented as:

${\mathrm{MO}}_{+}$

where M represents a group 1a or 2a metal.

How do you balance chemical equations for oxide reactions?

Balancing chemical equations for oxide reactions involves ensuring that the number of atoms of each element is the same on both sides of the equation. For example, to balance the reaction of lithium oxide with water:

${\mathrm{Li}}_2+H_{2}O\to {\mathrm{Li}}_2\left({\mathrm{OH}}_2\right)$

We need to ensure that there are 2 lithium atoms, 2 oxygen atoms, and 2 hydrogen atoms on both sides. Similarly, for the reaction of calcium oxide with hydrochloric acid:

${\mathrm{CaO}}_{+}$

We balance by ensuring there are 1 calcium, 2 chlorine, and 2 hydrogen atoms on both sides.