Railway Science (Chemistry-Chemical Reaction)

In the reaction, 2Al + Fe₂O₃ → Al₂O₃ + 2Fe, the substance that is the reducing agent is Al (Aluminium) and the substance that is the oxidizing agent is Fe (iron). The oxidation number of Al increases from 0 to +3 and the oxidation number of Fe decreases from +3 to 0.

It is the reaction of an acid and a base, which forms water and a salt. Precipitation reactions. Example : AgN𝑂₃ (aq) + KCl(aq) → AgCl + KN𝑂 . Combination Reaction - A chemical reaction where two or more elements or compounds combine to form a single product.
Example: 2𝐻₂(g) + 𝑂₂(g) → 2𝐻₂O(l).  Decomposition Reaction - Chemical reaction in which one reactant breaks down into two or more products. Example: 2HgO(s) →2Hg(l) + 𝑂₂ (g).

The oxidation state of Zinc reduces from +2 to 0 (ZnO is reduced to Zn), it is getting reduced, ZnO acts as an oxidising agent in the reaction: ZnO (Zinc Oxide) + C (Carbon) → Zn (Zinc) + CO (Carbon Monoxide). The oxidation state of Carbon increases from 0 to +2, C acts as a reducing agent.

Fe₂O₃ (Ferric Oxide) + 3CO (Carbon monoxide) → 3Fe (Iron) + 3C𝑂₂ (Carbon Dioxide). The oxidation state of Iron has reduced from +3 in Ferric oxide (oxidising agent) to 0 in Iron. The oxidation state of Carbon increases from +2 in Carbon monoxide (reducing agent) to +4 in Carbon dioxide.

In which oxygen is gained or hydrogen is lost, {2Cu (Copper) + 𝑂₂ (Oxygen) 2CuO  → (Copper Oxide)}. Addition reaction is an organic reaction where two or more molecules combine to form a larger one, {𝐶₂𝐻₄ (Ethylene) + C𝑙₂ (Chlorine) → 𝐶₂𝐻₄ C𝑙₂ (Ethylene Dichloride) }. Combustion reaction will always occur when a substance reacts with oxygen to release energy {C𝐻₄ (Methane) + 2𝑂₂ → C𝑂₂ + 2 𝐻₂O + heat). Substitution reaction: In which the functional group of one chemical compound is substituted by another group (𝐶₂𝐻₅OH  (Ethanol or Ethyl Alcohol) +  HI (Hydrogen Iodide) → 𝐶₂𝐻₅I (Ethyl Iodide) + 𝐻₂O).

Double displacement reaction is a type of chemical reaction in which two reactants exchange ions to form two new compounds. Example - AgNO₃ (aq) + NaCl (aq) AgCI (s) ( ) + NaNO₃ → ↓ (aq). The reaction of NaCl (Sodium chloride) and AgNO₃ (Silver nitrate) gives AgCl (Silver chloride) and NaNO₃ (Sodium nitrate) .

When acid is mixed with a solution of base it results in a neutralization reaction. Neutralization is an exothermic reaction which results in the formation of salt. Eg:- Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O, For the neutralization of acidic soils, farmers use lime (calcium oxide).
To neutralise the excess hydrochloric acid in the gut causing indigestion, antacid tablets contain bases such as magnesium hydroxide and magnesium carbonate.

Balanced chemical equations have the same number and type of each atom on both sides of the equation because a chemical equation must obey the law of conservation of mass and the law of constant proportions, i.e. the same number of atoms of each element must exist on the reactant side and the product side of the equation. Antoine Laurent Lavoisier discovered the law of conservation of mass. J. L. Proust (law of constant proportions).

Neutralization reaction : A chemical reaction in which an acid and base quantitatively react together to form salt and water as products. Example: HNO₃(aq)+KOH (aq) → KNO₃ (aq) + H₂O(I)

Thermal decomposition is a chemical reaction that happens when a compound breaks down when heated. Zinc carbonate is a white powdery solid. When it is heated strongly, it starts to turn yellow and decomposes carbon dioxide gas which forms a white precipitate in limewater.
2NaCl (molten)→ 2Na + Cl₂ (Electrolytic decomposition). 2AgCl→2Ag + Cl₂ (photolytic decomposition).