Railway Science (Chemistry-Chemical Reaction) (Part-II)

NaOH (Sodium Hydroxide) + HCl (Hydrochloric acid) → NaCl (Sodium Chloride) + 𝐻₂O (Water).
Neutralization reaction - A chemical reaction in which an acid and base quantitatively react together to form a salt and water as products.
There is a combination of H⁺ ions and OH⁻ ions which form water. Copper sulphate (CuSO₄), Barium Sulphate (BaSO₄), Copper chloride (CuCl₂).

CuSO4 (Copper Sulphate) + H₂S (Hydrogen Sulphide) → CuS (Copper sulfide) + H₂SO₄ (Sulphuric Acid). A double displacement reaction is a type of reaction where part of one reactant is replaced by part of another reactant. Double displacement reactions take the form: AB + CD → AD + CB.

Reactivity series of metals - K (Potassium) > Na (Sodium) > Ca (Calcium) > Mg (Magnesium) > Al (Aluminium) > Zn (Zinc) > Fe (Iron) > Pb (Lead) > H (Hydrogen) > Cu (Copper) > Ag (Silver) > Au (Gold). Metal which has High reactivity will replace metal which has comparatively low reactivity.

Oxidation is a process which involves the addition of oxygen or any electronegative element or the removal of hydrogen or any electropositive element. Photolytic decomposition reaction- It is a chemical reaction in which a chemical compound is broken down by photons.
Neutralization Reaction- It can be defined as a chemical reaction in which an acid and base quantitatively react together to form a salt and water as products. Exothermic reaction- A reaction in which energy is released in the form of light or heat.

Calcium hydroxide Ca(OH)₂ reacts slowly with the carbon dioxide (CO₂) in the air to form a thin layer of Calcium carbonate (CaCO₃). The layer is formed after two to three days of whitewashing and gives a shiny finish to the walls. Calcium carbonate is the chemical name of limestone.

When some granules of aluminum are added in the aqueous solution of copper sulphate which is blue in colour, the colour of the solution changed and it becomes colourless. This is because of the formation of Aluminium sulphate which is a salt.
It is soluble in water and is mainly used as a coagulating agent in the purification of drinking water and wastewater treatment plants, and also in paper manufacturing.

When one molecule of zinc and one molecule of sulphuric acid reacts it results in the production of one molecule of zinc sulphate and one molecule of hydrogen. This is a displacement reaction .
Because zinc is more reactive than hydrogen so it displaces hydrogen from its place and forms ZnSO₄ . Law of conservation of mass - When a chemical reaction occurs, the mass of the products should be equal to the mass of the reactants. So, the amount of the atoms in each element does not change in the chemical reaction.

Oxidation - The loss of electrons or gain of oxygen during a reaction by a molecule, atom or ion. Example - The reaction between magnesium metal and oxygen to form magnesium oxide involves the oxidation of magnesium.

Oxidised. Oxidation - The loss of electrons during a reaction by a molecule, atom or ion. Example of the oxidation reaction is : C + O₂ → CO₂ .
In this reaction, the addition of oxygen to carbon for the formation of carbon dioxide.

When barium chloride (BaCl₂) and sodium sulfate (Na₂SO₄), which leads to the formation of sodium chloride and barium sulfate. White color precipitate is formed due to the formation of barium sulfate.
The reaction Na₂SO₄(aq) + BaCl₂(aq) BaSO₄  → (s) + 2NaCl(aq) is an example of Double displacement reaction. The reaction between Na₂SO₄ + BaCl₂ is an endothermic reaction.

Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄ (s) + 2NaCl(aq).