Physical Science Important Reactions
All important balanced chemical equations for AP SSC Class 10 Physical Science — Ch.1 to Ch.4 (NCERT). Type, equation, and the key observation to remember for each reaction.
Ch. 1 — Chemical Reactions and Equations
2Mg + O₂ → 2MgO
Magnesium burns in air — bright white flame
CaCO₃ → CaO + CO₂
Limestone heated → quicklime + CO₂
2AgBr → 2Ag + Br₂
Silver bromide decomposes in sunlight (photography)
2H₂O → 2H₂ + O₂
Electrolysis of water — H₂ at cathode, O₂ at anode
Fe + CuSO₄ → FeSO₄ + Cu
Iron displaces copper from copper sulphate solution
Na₂SO₄ + BaCl₂ → BaSO₄↓ + 2NaCl
White precipitate of barium sulphate forms
CH₄ + 2O₂ → CO₂ + 2H₂O
Complete combustion of methane
2FeSO₄ → Fe₂O₃ + 2SO₂ + SO₃
Ferrous sulphate is oxidised on heating
Ch. 2 — Acids, Bases and Salts
Zn + H₂SO₄ → ZnSO₄ + H₂↑
Zinc reacts with dilute sulphuric acid
NaOH + HCl → NaCl + H₂O
Strong acid + strong base — heat is released
Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂↑
CO₂ turns lime water milky
NaHCO₃ + HCl → NaCl + H₂O + CO₂↑
Baking soda with acid
Ca(OH)₂ + CO₂ → CaCO₃↓ + H₂O
Limewater test — turns milky
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
Sodium sulphate (salt) formed
Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O
Milk of magnesia as antacid
NaCl + AgNO₃ → AgCl↓ + NaNO₃
White precipitate of silver chloride — test for Cl⁻
Ch. 3 — Metals and Non-metals
2Na + 2H₂O → 2NaOH + H₂↑
Sodium reacts vigorously with cold water
Mg + H₂O → MgO + H₂
Magnesium reacts with steam only
3Fe + 4H₂O → Fe₃O₄ + 4H₂
Iron with steam forms magnetic oxide
2Al + Fe₂O₃ → Al₂O₃ + 2Fe
Used in welding railway tracks — very exothermic
Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
Copper displaces silver (more reactive)
4Al + 3O₂ → 2Al₂O₃
Aluminium forms a protective oxide layer
Zn + CuSO₄ → ZnSO₄ + Cu
Blue colour of CuSO₄ fades as Cu deposits
2Cu + O₂ → 2CuO
Copper turns black on heating in air
Ch. 4 — Carbon and its Compounds
CH₄ + 2O₂ → CO₂ + 2H₂O
Complete combustion of methane (clean blue flame)
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Combustion of ethanol
CH₂=CH₂ + H₂ → CH₃CH₃
Ni catalyst; used in hardening vegetable oils
CH₂=CH₂ + Br₂ → CH₂BrCH₂Br
Bromine water decolourises — test for alkenes
C₂H₅OH + CH₃COOH ⇌ CH₃COOC₂H₅ + H₂O
Conc. H₂SO₄ catalyst; fruity smell ester formed
CH₃COOC₂H₅ + NaOH → CH₃COONa + C₂H₅OH
Soap making — base hydrolysis of ester
CH₄ + Cl₂ → CH₃Cl + HCl
Sunlight required; H replaced by Cl (halogenation)
2CH₃OH + 2Na → 2CH₃ONa + H₂↑
Alcohols react with sodium to release H₂