Oxides and Salts
Oxides are compounds of oxygen with elements, classified as acidic (non-metal), basic (metal), amphoteric, or neutral, which react with acids/bases to form salts and water. Salts are ionic compounds formed from these neutralization reactions, specifically when metal oxides (basic) react with acids or non-metal oxides (acidic) react with bases.
Key Types of Oxides and Their Behavior
Basic Oxides: Formed by metals (e.g.,
CuOcap C u cap O
𝐶𝑢𝑂
,
CaOcap C a cap O
𝐶𝑎𝑂
,
Na2Ocap N a sub 2 cap O
𝑁𝑎2𝑂
). They react with acids to form salt and water.
Example:
CaOcap C a cap O
𝐶𝑎𝑂
(calcium oxide) +
2HCl2 cap H cap C l
2𝐻𝐶𝑙
(hydrochloric acid)
→right arrow
→
CaCl2cap C a cap C l sub 2
𝐶𝑎𝐶𝑙2
(salt) +
H2Ocap H sub 2 cap O
𝐻2𝑂
.
Acidic Oxides: Formed by non-metals (e.g.,
SO2cap S cap O sub 2
𝑆𝑂2
,
CO2cap C cap O sub 2
𝐶𝑂2
). They react with bases to form salt and water.
Example:
CO2cap C cap O sub 2
𝐶𝑂2
(carbon dioxide) +
2NaOH2 cap N a cap O cap H
2𝑁𝑎𝑂𝐻
(sodium hydroxide)
→right arrow
→
Na2CO3cap N a sub 2 cap C cap O sub 3
𝑁𝑎2𝐶𝑂3
(salt) +
H2Ocap H sub 2 cap O
𝐻2𝑂
.
Amphoteric Oxides: Metal oxides that exhibit both acidic and basic properties, reacting with both acids and bases to produce salt and water (e.g.,
Al2O3cap A l sub 2 cap O sub 3
𝐴𝑙2𝑂3
,
ZnOcap Z n cap O
𝑍𝑛𝑂
).
Reaction with Acid:
Al2O3cap A l sub 2 cap O sub 3
𝐴𝑙2𝑂3
+
6HCl6 cap H cap C l
6𝐻𝐶𝑙
→right arrow
→
2AlCl32 cap A l cap C l sub 3
2𝐴𝑙𝐶𝑙3
+
3H2O3 cap H sub 2 cap O
3𝐻2𝑂
.
Reaction with Base:
Al2O3cap A l sub 2 cap O sub 3
𝐴𝑙2𝑂3
+
2NaOH2 cap N a cap O cap H
2𝑁𝑎𝑂𝐻
→right arrow
→
2NaAlO22 cap N a cap A l cap O sub 2
2𝑁𝑎𝐴𝑙𝑂2
+
H2Ocap H sub 2 cap O
𝐻2𝑂
.
Neutral Oxides: Show neither acidic nor basic properties and do not form salts (e.g.,
N2Ocap N sub 2 cap O
𝑁2𝑂
,
NOcap N cap O
𝑁𝑂
,
COcap C cap O
𝐶𝑂
).
Salts
Salts are produced through the neutralization reaction between oxides and acids/bases.
Formation: Metal oxides (bases) + Acid
→right arrow
→
Salt + Water.
Examples: Calcium chloride (
CaCl2cap C a cap C l sub 2
𝐶𝑎𝐶𝑙2
), Sodium carbonate (
Na2CO3cap N a sub 2 cap C cap O sub 3
𝑁𝑎2𝐶𝑂3
), Copper(II) sulfate (
CuSO4cap C u cap S cap O sub 4
𝐶𝑢𝑆𝑂4
).
This video explains the different types of oxides and their reactions with acids and bases: