CHEMISTRY (Part-VI) (Railway)

Oxidation is a chemical reaction involving addition of oxygen to a substance or removal of hydrogen from a substance.

● On the other hand, Reduction involves addition of hydrogen to a substance or removal of oxygen from a substance.

● So, the next homologous series member of compound C₆H₁₀ will be C₇H₁₂.

There are 118 elements currently on the periodic table.

Several elements have only been found in laboratories and nuclear accelerators. Such elements are called synthetic elements.

● There are 24 known synthetic elements that do not occur naturally on Earth.

Sodium carbonate decahydrate (Na₂CO₃·10H₂O) is also known as washing soda.

● It is the most common hydrate of sodium carbonate containing 10 molecules of water of crystallization.
● Soda ash is dissolved in water and crystallized to get washing soda.

A strong acid is one that completely ionizes in water to form a large amount of hydrogen ions whereas a weak acid only partially ionizes in water and thus produces a small amount of hydrogen ions.

● CH₃COOH, H₂CO₃ and H₂SO₃ are weak acids.
● HCl, H₂SO₄ and HNO₃ are strong acids.

Plastic is non-biodegradable. It takes several years for plastic to decompose, and it is not environment friendly.

● They are made from synthetic polymers that cannot be degraded by any microbial action.

● On the contrary, substances such as cotton, paper, and food are prone to decomposition by microbial action and are considered biodegradable wastes.

Atomic number of Nitrogen is 7. Its electronic configuration is 2, 5. So, it is clear that nitrogen has 5 electrons in its outermost shell.

● To complete its octet, nitrogen can either receive 3 electrons or lose 5 electrons. So, its valency is 3 or 5.

● The valency of Lithium is 1, Calcium: 2 and Aluminium: +3

The reaction in that two or more reactant molecules combine to form one product is called as "combination reaction".

● N₂ + H₂ → 2NH₃ is an example of a combination reaction. Nitrogen and Hydrogen combine in this reaction to give Ammonia.

Electrolytic decomposition results when an electric current is passed through the aqueous solution of a compound.

● When electrical energy from a battery is passed through water, the water dissociates into the diatomic molecules of hydrogen and oxygen.

● 2H₂O → 2H₂ + O₂