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.

The hazards of working in the glass bangle industry as follows :

Workers in the glass bangle industry have to work in very high temperature around the glass furnaces. They work in dinky cells without air and light. They don't get any daylight. Thus they lose the brightness of their eyes. The Powder from the polishing of bangles also blinds them.

In Firozabad about 20,000 children have to work in glass bangle industry in dark places all day long.

Child labour should be eliminated because it takes away from the child his childhood and the prospect of elementary education. Moreover, since the child labourers are cheap, and consequently engaged in hazardous and dangerous employment, they are often vulnerable to mental and physical illness. Entering the workforce too early diminishes a child's lifetime earning potential. Child laborers have very limited ability to take advantage of educational opportunities that would help them receive better-paying jobs as adults.

An emf induced by the motion of the conductor across the magnetic field is a motional electromotive force. The equation is given by E = -vLB. This equation is true as long as the velocity, field, and length are mutually perpendicular. The minus sign associated with the Lenz’s law.

Let us take a rectangular coil, a metal rod of length L, moving with velocity V, through a magnetic field B. There is a magnetic field at some location.

Length, velocity and magnetic field should always be at a right angle with each other. The direction of the magnetic field is going inside. Assume the metal rod is frictionless that means there is no loss of energy due to friction and we apply a uniform magnetic field. The conductor rod is moved with a constant velocity and placed in the magnetic field.

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.

Tertiary activities are related to the service sector. Manpower is an important component of the service sector as most of the tertiary activities are performed by skilled labour, professionally trained experts and consultants.

The 1960s decade was labelled as the ‘dangerous decade’ when unresolved problems like poverty, inequality, communal and religious divisions etc. could lead to a failure of the democratic project or even the disintegration of the country.

1. Symbolic Paintings: Radha and Krishna have been shown in the form of soul and God. Radha and Krishna have been beautifully painted in all schools of Rajasthan.

2. Linear Beauty: Rhythmic and graceful lines have been used in all sub-schools of Rajasthan. The thin lines are full of softness in paintings.

3. Painting of literature: In literature Geet-Govind, Bhagwat Puran, Rag Mala, ‘Ragas and Raginis’ have been beautifully painted in Rajasthan Schools of Art.

4. Religious Themes: Religious themes based on Ramayana and Bhagwat Geeta has been beautifully painted. 8. Landscape or Seasons painting: Landscape has been beautifully painted in different seasons. Painting of ‘Barah Masa’ is the depiction of twelve months.

5. Effect of Folk Art: Folk Art is prominent in all Rajasthani painting.

6. Night Scenes: Night scenes are painted in very attractive way in which Black or Smoke grey colour, White colour and Yellow golden colours are used. Moon and stars have been painted in white colour.