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Carbon in all its allotropic forms, burns in oxygen to give carbon dioxide along with the release of heat and light. Most carbon compounds also release a large amount of heat and light on burning. Hence carbon and its compounds are used as fuels for most applications.

Carbon and its compounds undergo combustion to produce heat, the amount of heat released can be handled and used so they are used as fuels for most applications. 

Most of the carbon compounds give a lot of heat and light when burnt in air. Saturated hydrocarbons burn with a clean flame and no smoke is produced. The carbon compounds, used as a fuel, have high calorific values. Therefore, carbon and its compounds are used as fuels for most applications.

A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called homologous series.

Consider the homologous series of alcohols – methanol, ethanol, etc. Note that methanol (CH₃OH) is obtained by replacing one of the H atoms with –OH group. Similarly, the –OH group replaces one of the H atoms of ethane (CH₃CH₃) to form ethanol (CH₃CH₂OH) and so on. The chemical properties of these compounds are similar. The successive members of the homologous series differ by a –CH2 unit.

For example, CH₃OH and CH₃CH₂OH, CH₃CH₂OH and CH₃CH₂CH₂OH differ by a –CH₂ unit.

Also, members of a homologous series can be represented using a general formula. In the case of alcohols, the general formula is C_nH_2n+1O, where ‘n’ is the number of carbon atoms.

Hard water contains salts of calcium and magnesium. When soap molecule comes in contact with these salts it forms a curdy white precipitate (compound insoluble in water) called scum. 

Soap + Hard water ⎯→ scum 

Soap does not work properly when the water is hard. A soap is a sodium or potassium salt of long chain fatty acids. Hard water contains salts of calcium and magnesium. When soap is added to hard water, calcium and magnesium ions present in water displace sodium or potassium ions from the soap molecules forming an insoluble substance called scum. A lot of soap is wasted in the process.

Ordinary soaps when treated with hard water, precipitate as salts of calcium and magnesium. They appear at the surface of the cloth as sticky grey scum. Thus, the soaps cannot be used conveniently in hard water.

Scum is an insoluble precipitate formed due to the reaction of soap with calcium and magnesium salts present in hard water. As a result, soap does not form lather in hard water, making its cleansing action less effective in hard water.

The two properties of acetic acid can be used to identify acetic acid in the test tube, containing acetic acid and water are: Acetic acid reacts with NaHCO₃ and the colour change with universal indicator.

Triploblastic: Different tissues are formed from three layers of cells.

Soaps, which are prepared by the saponification of oils or fats with caustic soda (sodium hydroxide), are known as hard soaps. They are usually used for washing purposes.

Coelom: Space present inside the body.

Ca(HCO₃)₂(aq) + 2Na⁺ -stearate (aq)↓ → Ca(stearate)₂ (s) + 2NaHCO₃ (aq)

CaSO₄ (aq) + 2Na⁺ -stearate (aq) ↓ → Ca(stearate)₂ (s) + Na₂SO₄(aq)

(a) (i) Gallium (ii) Germanium.

(b) 4th period .

(c) Gallium: 13th group; Germanium: 14th group .

(d) Gallium: Metal; Germanium: Metalloid .

(e) Gallium: 3 ; Germanium: 4 .

Pseudocolor: False cavity present inside the body of an organism.

Yes. Hydrogen ions provided by HCI makes water hard.

H⁺ + Na⁺ stearate^- → Steric acid + Na⁺

(a) Newlands’ law of octaves .

(b) Newlands .

(c) This classification of elements is compared with a characteristic of musical scale because in this classification, the repetition in the properties of elements is just like the repetition of eighth note in an octave of music .

(d) This classification of elements could be applied only up to the element calcium and not beyond that .

To determine whether a given water sample is of hard water or soft water, one can use soap. 

Soap produces lather in soft water whereas soap does not produce lather in hard water due to the formation of scum (insoluble precipitate). Scum is a result of reaction of soap with calcium and magnesium ions present in the hard water.

2RCOONa + Ca²⁺ → (RCOO)₂Ca↓ (Scum) + 2Na⁺ 

Notochord: A cylindrical chord/string-like structure which ¡s along mid-dorsal line in all chordates.

The element whose allotropic form is graphite is-

Carbon.

The following statement is-

False

Friedrich Wohler.

Zinc Sulphate – Displacement

Zn(OH)₂ + H₂SO₄ ⟶ ZnSO₄ + 2H₂O

Ferrous sulphide – synthesis

Fe + S ⟶ FeS

Barium sulphate – Precipitation

BaCI₂+H₂SO₄ ⟶ BaSO₄ + 2HCI

Ferric sulphate – Oxidation

Fe + H₂SO₄ ⟶ FeSO₄ + H₂

Sodium sulphate – Neutralisation

2NaOH + H₂SO₄ ⟶ Na₂SO₄ + 2H₂O

Chemically the term alcohol refers to a group of organic compounds, having -OH group in their composition. But the word alcohol used by the common man refers to ethyl alcohol or ethanol. It has a variety of uses, especially as a solvent. But by far the greatest use of alcohol is in the form of alcoholic beverages, such as wine, beer, rum, brandy, whisky etc. In small quantities it may serve as a source of energy, but in large amounts, it affects the nervous system. The person experiences loss of control over muscles and loses his or her sense of balance and mental ability. It can be a habit forming activity. If consumed over a period of time, alcohol can ruin one's health especially the liver, which gets affected by cirrhosis. This type of consumption can be fatal and ruins one's family life.

Protina, shakthi are the maize hybrids rich in amino acid lysin.

(2) Pb metal

Correct option is (d) Quality control.

Correct option is (d) Requires no formal position.

Correct option is (d) Improved lateral communications.

Correct option is (d) Expert.

Public Works Department

National Highways Authority of India

International Airports Authority of India

The roads which connect the state capital, important cities, towns and district headquarters, and connect with national highways and highways to neighbouring states sire called state highways.

Soils of India: Six Different Types of Soils Found in India are as follows: 

Soil is our prime natural and economic resource. Soils in India differ in composition and structure. 

1. Alluvial Soils : These are formed by the deposition of sediments by rivers. They are rich in humus and very fertile. They are found in Great Northern plain, lower valleys of Narmada and Tapti and Northern Gujarat. These soils are renewed every year. 

2. Black Soils : These soils are made up of volcanic rocks and lava-flow. It is concentrated over Deccan Lava Tract which includes parts of Maharashtra, Chhattisgarh, Madhya Pradesh, Gujarat, Andhra Pradesh and Tamil Nadu. It consists of Lime, Iron, Magnesium and also Potash but lacks in Phosphorus, Nitrogen and Organic matter. 

3. Red Soils : These are derived from weathering of ancient metamorphic rocks of Deccan Plateau. Its redness is due to iron composition. When iron content is lower it is yellow or brown. They cover almost the whole of Tamil Nadu, Andhra Pradesh, Chhattisgarh, Karnataka, Maharashtra and parts of Orissa. 

4. Laterite Soils : These soils are formed due to in-tense leaching and are well developed on the sum-mits of hills and uplands. They are commonly found in Kerala, Tamil Nadu, Maharashtra, Chhattisgarh and hilly areas of Orissa and Assam. 

5. Mountain Soils : These soils are formed as a result of the accumulation of organic matter derived from forest growth. They are found in Himalayan region and vary in different regions according to altitude. Tea is grown in those areas which receive sufficient rainfall. 

6. Desert Soils : In the desert regions of Rajasthan, soils are not well developed. As evaporation is in excess of rainfall, the soil has a high salt content and saline layer forms a hard crust. These soils are gen-erally sandy and deficient in organic matter.

Correct option is (C) Financially sound company

Temperature changes result in expansion and contraction of rocks during day and night resulting in degradation of rocks. In the temperate latitudes the frost shatters the rocks.

The minerals contained in the rocks react with the gases and moisture in the air like oxygen reacts with iron and causes the rocks to rust and get eroded.

Human activities like mining, quarrying deforestation, tunnelling, road construction and farming affect the weathering.

Landslides and soil erosion are two major effects of weathering.

The decaying remains of dead plants in soil tend to form organic acid which when dissolved in water cause chemical weathering. ants, earthworms and burrowing animals such as rats and rabbits looses soil and make tunnels causing weathering.

Waters pays an important role in chemical  weathering. the carbon dioxide in atmosphere dissolves in rainwater and from carbonic acid and reacts with minerals in the rocks. the soluble minerals dissolve in water such as feedspar and potash absorb water and become a powderd  mass similarily soluble minerals dissove and are removed , resulting in the breakup of the rocks . Rock salt, gypsum, and silica are examples of minerals theat are highly soluble and when rainfall falls they decompose.

Factors that affect weathering are : 

1. Local climate 

2. Mineral composition 

3. Structure of rock 

4. Human activities 

5. Amount of exposed or bare rocks surface, and human activities.

Degradation : The process by which rock materials from the earth’s surface are removed resulting in general lowering of land surfaces. 

Aggradation : The process by which the rock material removed from the earth’s surface and then deposited in depressions such as valleys, lakes and sea beds. The depression fills

The topmost layer is the topsoil (Layer D) which consists of clay, silt, sand and humus.

1. The sperms in a human male are produced in Testes.

2. Testosterone hormones is secreted by the interstitial cells.

3. The surgical sterilization of male is known as Vasectomy.

4. Fertilization of human egg by the sperm normally occurs in the Oviduct (fallopian tube).

5. The period of complete development of the foetus till birth is termed Gestation.

Monascus – Statin – Cholesterol Streptococcus – Streptokinase – Cholestrol lowering

Pencillium – Penicillin – Antibiotic

Trichoderma – Cyclosporin-A – Immuno suppressant

The monthly discharge of blood and disintegrated tissues in a human female is Menstruation. 

(a) Yes.

(b) Rhizohium found in the root nodules in the pea plant can x atmospheric nitrogen into nitrates and in-creases fertility of soil.

Evidence for Natural selection and explanations like origin of antibiotic resistant varieties or elimination of sensitive varieties or Natural selection by Anthropo-genic action.