• Diamond: It is extremely hard, transparent crystal, with the carbon atoms arranged in a tetrahedral lattice. This allotrope of carbon is a poor electrical conductor and an excellent thermal conductor.
• Lonsdaleite: These are also called hexagonal diamond.
• Graphene: It is the basic structural element of other allotropes, nanotubes, charcoal, and fullerenes.
• Q-carbon: These carbon allotropes are ferromagnetic, tough, and brilliant crystal structure that is harder and brighter than diamonds.
• Graphite: It is a soft, black, flaky solid, a moderate electrical conductor. The C atoms are bonded in flat hexagonal lattices (graphene), which are then layered in sheets.
• Linear acetylenic carbon (Carbyne)
• Amorphous carbon
• Fullerenes, including Buckminsterfullerene, also known as “buckyballs”, such as C60.
• Carbon nanotubes: Allotropes of carbon with a cylindrical nanostructure.

• Ozone used at water treatment plants without filtration systems.
• Ozone may also be formed by commonly used equipment such as photocopiers, laser printers, and other electrical devices.
• In medicine, by limiting the effects of bacteria, viruses, fungi, yeast, and protozoa, ozone therapy is used to disinfect and treat diseases.
• Several ozone-depleting compounds possess properties that make them good refrigerants that is, they can efficiently transfer heat from one location to another.

Resonance structures are sets of Lewis structures that describe the delocalization of electrons in a polyatomic ion or a molecule.

In many cases, a single Lewis structure fails to explain the bonding in a molecule/polyatomic ion due to the presence of partial charges and fractional bonds in it. In such cases, resonance structures are used to describe chemical bonding.

Resonance structure of ozone (O)₃

Ozone performs an essential function by forming a ozone layer which shields the surface of the earth from the entry of UV rays from the sun.

"Nascent" just means newly-formed. A single oxygen atom, not yet bonded to anything.

1. Neutral Oxide is one which neither has an acidic characteristic or a basic one.

• It is a colourless, odourless diatomic gas and paramagnetic in nature.
• Oxygen is highly reactive non-metal.
• This diatomic gas is a strong oxidizing gas.
2SO2 + O2 → 2SO3
• It is second most electronegative element after fluorine.
• Dioxygen reacts with metals, non-metals to give oxides of the respective element.
2Ca + O2 → 2CaO

Fractional distillation is a type of distillation which involves the separation of miscible liquids. The process involves repeated distillations and condensations and the mixture is usually separated into component parts. The separation happens when the mixture is heated at a certain temperature where fractions of the mixture start to vaporize.

KMnO₄ when heated to 473 K, readily decomposes giving oxygen. At red heat, potassium permanganate decomposes into potassium manganate (K2MnO3) and oxygen.

1) Rhombic Sulphur

• We find them as yellow and translucent crystals.
• Rhombic Sulphur has a melting point of 114^o C.
• The density of rhombic Sulphur is 2.08 g/cm³
• It is stable at temperatures below 96^oC.

2) Monoclinic Sulphur

• These are transparent and amber crystals.
• They have a melting point of 119^oC.
• The density of monoclinic sulphur is 1.98 gcm³
• It is unstable at temperatures below 96^oC and changes into rhombic form.
• We must remember that at a temperature of 96^oC or above, rhombic sulphur changes to kaleidoscopic or prismatic sulphur. At 96^oC or beneath, kaleidoscopic or prismatic sulphur changes to rhombic sulphur.
• These allotropes that alter their configuration from one form to another by a change in the temperature are Enantiotropic Allotropes.

1) Rhombic Sulphur

• We find them as yellow and translucent crystals.
• Rhombic Sulphur has a melting point of 114^o C.
• The density of rhombic Sulphur is 2.08 g/cm³
• It is stable at temperatures below 96^oC.

2) Monoclinic Sulphur

• These are transparent and amber crystals.
• They have a melting point of 119^oC.
• The density of monoclinic sulphur is 1.98 gcm³
• It is unstable at temperatures below 96^oC and changes into rhombic form.
• We must remember that at a temperature of 96^oC or above, rhombic sulphur changes to kaleidoscopic or prismatic sulphur. At 96^oC or beneath, kaleidoscopic or prismatic sulphur changes to rhombic sulphur.
• These allotropes that alter their configuration from one form to another by a change in the temperature are Enantiotropic Allotropes.

The density of material shows the denseness of that material in a specific given area. A material’s density is defined as its mass per unit volume. Density is essentially a measurement of how tightly matter is packed together. 

Mathematically, the density of an object is expressed as follows:

Density=Mass/Volume ρ = mv

Where,

• ρ is the density
• m is the mass
• V is the volume

Preparation of Sulphur Dioxide

1. In the laboratory, sulphur dioxide is prepared by the reaction of metallic sulphite or a metallic bisulphite with dilute acid. For example, a reaction between the dilute sulphuric acid and sodium sulphite will result in the formation of SO₂.

Na₂SO₃ + H₂SO₄ → Na₂SO₄ + H₂O + SO₂

2. Commercially it is obtained as a by-product released from the roasting of sulphide ores. The gas obtained is dried, liquefied and then stored in steel cylinders.

4FeS₂ (s) + 11 O₂ (g) →2Fe₂O₃ (s) + 8SO₂ (g)

Properties of Sulphur Dioxide

• It is a colourless gas with a rotten egg odour. It is highly soluble in water.
• It liquefies easily.
• SO₂ dissolves in water to form sulphurous acid due to which it possesses an acidic character.

H₂O + SO₂ → H₂SO₃

• It does not support combustion nor is it combustible.
• SO₂ is a strong oxidizing agent.

2H₂S + SO₂ → 3S + 2H₂O

• It also acts as a reducing agent.

SO₂ + 2H₂O → H₂SO₄ + 2H

Uses of Sulphur Dioxide

• In the food industries, as a food preservative.
• It acts as a bleaching agent to remove the excess chlorine and as a disinfectant.
• In cold storage plant, it acts as a refrigerant.
• It is used as a reagent and a solvent in the laboratory.

Physical Properties of Ozone – O₃

Uses of Ozone – O₃

• Ozone used at water treatment plants without filtration systems.
• Ozone may also be formed by commonly used equipment such as photocopiers, laser printers, and other electrical devices.
• In medicine, by limiting the effects of bacteria, viruses, fungi, yeast, and protozoa, ozone therapy is used to disinfect and treat diseases.
• Several ozone-depleting compounds possess properties that make them good refrigerants that is, they can efficiently transfer heat from one location to another.

Industrial Method of Preparation

Hydrogen peroxide is prepared by the electrolysis of 30% ice-cold H₂SO₄. When acidified sulfate solution is electrolyzed at high current density, peroxodisulphate is obtained. Peroxodisulphate is then hydrolyzed to get hydrogen peroxide.

2HSO^–₄(aq) [Electrolysis] → HO₃SOOSO₃H(aq) [Hydrolysis] → 2HSO^–₄(aq)+2H+(aq)+H₂O₂(aq)

An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bond to oxygen that can dissociate to produce the H+ cation and the anion of the acid. An oxoacid is an acid that contains oxygen. ... For example, chlorine has the four following oxoacids: hypochlorous acid HClO. chlorous acid HClO. ... perchloric acid HClO.

Specific Gravity or relative gravity is a dimensionless quantity that is defined as the ratio of the density of a substance to the density of the water at a specified temperature and is expressed as

SG=ρsubstance/ ρH2O

It is common to use the density of wate<a href="https://byjus.com/physics/density-of-water/">r</a> at 4 ^oC as a reference point as water at this point has the highest density of 1000 kg/m³.

Physical Properties of Ozone – O₃

Uses of Ozone – O₃

• Ozone used at water treatment plants without filtration systems.
• Ozone may also be formed by commonly used equipment such as photocopiers, laser printers, and other electrical devices.
• In medicine, by limiting the effects of bacteria, viruses, fungi, yeast, and protozoa, ozone therapy is used to disinfect and treat diseases.
• Several ozone-depleting compounds possess properties that make them good refrigerants that is, they can efficiently transfer heat from one location to another.

Chlorobenzene is less reactive towards nucleophilic substitution reaction because of the following reasons:

(1) Resonance effect: The electron pair on chlorine atom is in conjugation with the electrons of the benzene ring which results in the following resonance structures:

This results in delocalization of the electrons of C - Cl bond and a partial double bond character develops in the bond, which makes it difficult for the Nucleophile to cleave the C - Cl bond.

(2) Polarity of the C-Cl bond: The sp2 hybridized carbon atom involved in C-Cl bond in chlorobenzene is more electronegative than the sp3 hybrid carbon atom in alkyl halide. Therefore, this sp2 hybridised carbon atom has less tendency to release electrons to the Cl atom. Thus, lower the polarity of C-Cl, lesser is the reactivity.

The given compound 'A' is calcium oxychloride because it is a oxidising agent and in open it reacts with CO₂ to give pungent smelling chlorine gas. 

CaOCl₂ + CO₂  → CaCO₃ + Cl₂ It is prepared by the action of dry slaked lime with chlorine gas. 

Ca(OH)₂ + Cl₂ →  CaOCl₂ + H₂O 

Calcium oxychloride is commercially known as Bleaching powder.