krit.club logo

Acids, Bases and Salts - Types of oxides

Grade 11IGCSEChemistry

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

Oxides are binary compounds formed by the reaction of an element with oxygen. They are classified based on their acid-base behavior into four categories: acidic, basic, amphoteric, and neutral.

•

Acidic oxides are generally oxides of non-metals (e.g., SO2SO_2, CO2CO_2, P4O10P_4O_{10}). They react with bases to form a salt and water, and most dissolve in water to form acidic solutions like H2SO4H_2SO_4 or H2CO3H_2CO_3.

•

Basic oxides are generally oxides of metals (e.g., CaOCaO, CuOCuO, MgOMgO). They react with acids to form a salt and water. Soluble basic oxides are called alkalis and form hydroxide ions (OH−OH^-) in water.

•

Amphoteric oxides are metal oxides that show both acidic and basic properties. Examples include Al2O3Al_2O_3 and ZnOZnO. They can react with both strong acids and strong bases to form salts and water.

•

Neutral oxides are non-metal oxides that do not react with either acids or bases. Common examples include COCO, NONO, and N2ON_2O.

📐Formulae

Basic Oxide+Acid→Salt+WaterBasic\ Oxide + Acid \rightarrow Salt + Water

Acidic Oxide+Base→Salt+WaterAcidic\ Oxide + Base \rightarrow Salt + Water

Na2O(s)+H2O(l)→2NaOH(aq)Na_2O(s) + H_2O(l) \rightarrow 2NaOH(aq)

CO2(g)+2NaOH(aq)→Na2CO3(aq)+H2O(l)CO_2(g) + 2NaOH(aq) \rightarrow Na_2CO_3(aq) + H_2O(l)

ZnO(s)+2HCl(aq)→ZnCl2(aq)+H2O(l)ZnO(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2O(l)

ZnO(s)+2NaOH(aq)+H2O(l)→Na2[Zn(OH)4](aq)ZnO(s) + 2NaOH(aq) + H_2O(l) \rightarrow Na_2[Zn(OH)_4](aq)

💡Examples

Problem 1:

Classify the following oxides as acidic, basic, amphoteric, or neutral: SO3SO_3, MgOMgO, COCO, and Al2O3Al_2O_3.

Solution:

SO3SO_3: Acidic; MgOMgO: Basic; COCO: Neutral; Al2O3Al_2O_3: Amphoteric.

Explanation:

SO3SO_3 is a non-metal oxide that forms H2SO4H_2SO_4 in water. MgOMgO is a metal oxide that reacts with acids. COCO does not react with acids or bases. Al2O3Al_2O_3 is a specific metal oxide known to react with both HClHCl and NaOHNaOH.

Problem 2:

Write the balanced chemical equation for the reaction between Aluminum oxide (Al2O3Al_2O_3) and Hydrochloric acid (HClHCl).

Solution:

Al2O3(s)+6HCl(aq)→2AlCl3(aq)+3H2O(l)Al_2O_3(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2O(l)

Explanation:

In this reaction, the amphoteric oxide Al2O3Al_2O_3 acts as a base, reacting with the acid HClHCl to produce the salt Aluminum chloride and water.

Problem 3:

Predict the observation when SO2SO_2 gas is bubbled through a solution of universal indicator.

Solution:

The indicator turns red or orange.

Explanation:

SO2SO_2 is an acidic oxide. It reacts with water to form sulfurous acid (H2SO3H_2SO_3), which releases H+H^+ ions, lowering the pH and changing the color of the indicator.

Types of oxides - Revision Notes & Key Formulas | IGCSE Grade 11 Chemistry