100 Most Important Oxides & Their Nature
One of the most common questions in Inorganic Chemistry competitive exams asks you to identify or arrange oxides based on their acidic, basic, or amphoteric nature. Understanding these trends is crucial for predicting chemical reactions, especially hydrolysis.
We have compiled the top 100 most important oxides, completely categorized for easy memorization. Bookmark this page for your final revision!
⚖️ Quick Rules of Thumb
🔥 1. Acidic Oxides
Generally oxides of non-metals & high oxidation state metals; they dissolve in water to give acids.
| No. | Oxide | Nature | Reaction Product (Acid formed) |
|---|---|---|---|
| 1 | CO2 | Acidic | Forms H2CO3 |
| 2 | SO2 | Acidic | Forms H2SO3 |
| 3 | SO3 | Acidic | Forms H2SO4 |
| 4 | NO2 | Acidic | Forms HNO3 / HNO2 |
| 5 | N2O3 | Acidic | Forms HNO2 |
| 6 | N2O5 | Acidic | Forms HNO3 |
| 7 | Cl2O | Acidic | Forms HClO |
| 8 | Cl2O7 | Acidic | Forms HClO4 |
| 9 | Br2O5 | Acidic | Forms HBrO3 |
| 10 | I2O5 | Acidic | Forms HIO3 |
| 11 | P2O3 | Acidic | Forms H3PO3 |
| 12 | P2O5 | Acidic | Forms H3PO4 |
| 13 | B2O3 | Acidic | Forms H3BO3 |
| 14 | SiO2 | Acidic | Forms H2SiO3 |
| 15 | As2O5 | Acidic | Forms H3AsO4 |
| 16 | V2O5 | Acidic | Forms Vanadic acid, HVO3 |
| 17 | CrO3 | Acidic | Forms H2CrO4 |
| 18 | Mn2O7 | Acidic | Forms HMnO4 |
| 19 | Re2O7 | Acidic | Forms HReO4 |
| 20 | OsO4 | Acidic | Also acts as a strong oxidizer |
💧 2. Basic Oxides
Generally oxides of metals in low oxidation states; they react with acids to form salts.
| No. | Oxide | Nature & Notes |
|---|---|---|
| 21 | Na2O | Basic (forms NaOH) |
| 22 | K2O | Basic (forms KOH) |
| 23 | Rb2O | Basic |
| 24 | Cs2O | Basic |
| 25 | Li2O | Basic (forms LiOH) |
| 26 | CaO | Basic (Lime, forms Ca(OH)2) |
| 27 | SrO | Basic |
| 28 | BaO | Basic |
| 29 | MgO | Basic (Slightly amphoteric in very strong acid/base) |
| 30 | BeO | Weakly amphoteric, but often considered basic in general trends |
| 31 | Cu2O | Basic |
| 32 | FeO | Basic |
| 33 | MnO | Basic |
| 34 | PbO | Basic (Though amphoteric tendencies exist) |
| 35 | SnO | Basic (But also amphoteric nature shown) |
| 36 | CoO | Basic |
| 37 | NiO | Basic |
| 38 | ZnO | Basic (At high base conc. amphoteric, but generally basic) |
| 39 | HgO | Weakly basic |
| 40 | Ag2O | Basic |
⚖️ 3. Amphoteric Oxides
React with both acids & bases; characteristic of metalloids and some transition metals.
| No. | Oxide | Nature |
|---|---|---|
| 41 | Al2O3 | Amphoteric |
| 42 | ZnO | Amphoteric |
| 43 | PbO | Amphoteric |
| 44 | SnO | Amphoteric |
| 45 | SnO2 | Amphoteric |
| 46 | PbO2 | Amphoteric |
| 47 | Cr2O3 | Amphoteric |
| 48 | BeO | Amphoteric |
| 49 | Ga2O3 | Amphoteric |
| 50 | In2O3 | Amphoteric |
| 51 | Tl2O3 | Amphoteric |
| 52 | V2O3 | Amphoteric |
| 53 | TiO2 | Amphoteric |
| 54 | ZrO2 | Amphoteric |
| 55 | HfO2 | Amphoteric |
| 56 | Nb2O5 | Amphoteric |
| 57 | Ta2O5 | Amphoteric |
| 58 | MoO2 | Amphoteric |
| 59 | WO3 | Amphoteric |
| 60 | UO2 | Amphoteric |
🍃 4. Neutral Oxides
Do not react with acids or bases; mostly diatomic nonmetal oxides.
| No. | Oxide | Nature & Notes |
|---|---|---|
| 61 | CO | Neutral |
| 62 | NO | Neutral |
| 63 | N2O | Neutral |
| 64 | H2O | Neutral (Though amphoteric in Bronsted sense) |
| 65 | O2 | Neutral (Does not react like acid/base) |
| 66 | NO2 | Shows both acidic + neutral behavior (borderline) |
| 67 | SO | Neutral (Rare, unstable) |
| 68 | Cl2O6 | Neutral / acidic mix behavior |
| 69 | N2O4 | Neutral in solid, acid anhydride in gas |
| 70 | SiO | Neutral |
⚙️ 5. Transition Metal Oxides
Highly varied nature! The acidity increases as the oxidation state of the metal increases.
| No. | Metal Element | Oxide Formula | Nature |
|---|---|---|---|
| 71 | Vanadium | V2O3 | Amphoteric |
| 72 | VO2 | Amphoteric | |
| 73 | V2O5 | Acidic | |
| 74 | Chromium | CrO | Basic |
| 75 | Cr2O3 | Amphoteric | |
| 76 | CrO3 | Acidic | |
| 77 | Manganese | MnO | Basic |
| 78 | Mn2O3 | Amphoteric | |
| 79 | MnO2 | Amphoteric | |
| 80 | Mn2O7 | Acidic | |
| 81 | Iron | FeO | Basic |
| 82 | Fe2O3 | Amphoteric (but largely basic) | |
| 83 | Fe3O4 | Mixed oxide (FeO + Fe2O3) | |
| 84 | Cobalt | CoO | Basic |
| 85 | Co2O3 | Amphoteric | |
| 86 | Nickel | NiO | Basic |
| 87 | Ni2O3 | Amphoteric | |
| 88 | Copper | Cu2O | Basic |
| 89 | CuO | Amphoteric | |
| 90 | Zinc | ZnO | Amphoteric |
| 91 | Lead | PbO | Amphoteric |
| 92 | PbO2 | Amphoteric | |
| 93 | Tin | SnO | Amphoteric |
| 94 | SnO2 | Amphoteric | |
| 95 | Silver | Ag2O | Basic |
| 96 | Mercury | Hg2O | Basic |
| 97 | HgO | Basic | |
| 98 | Titanium & Zirconium | TiO2 | Amphoteric |
| 99 | ZrO2 | Amphoteric | |
| 100 | Uranium | U3O8 | Amphoteric |
Frequently Asked Questions (FAQs)
What are the 4 neutral oxides?
The four main neutral oxides are Carbon monoxide (CO), Nitric oxide (NO), Nitrous oxide (N2O), and Water (H2O). They do not react with acids or bases in aqueous solutions.
How does oxidation state affect the acidic nature of an oxide?
As the oxidation state of the central metal atom increases, its acidic nature increases. For example, MnO (+2) is basic, MnO2 (+4) is amphoteric, and Mn2O7 (+7) is highly acidic.
Master Some Basic Concepts of Chemistry
Notes • PYQs • MCQs • Revision • JEE • NEET • CBSE
Explore Complete Chapter →
No comments:
Post a Comment