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Properties and uses of sodium chloride:

• Common salt is a colourless and crystalline ionic compound. There is no water of crystallization in its crystalline structure.
• It is a neutral salt, salty in taste.
• This compound is used for the production of salts like Na₂CO₃ , NaHCO₃.
• When an electric current is passed through a saturated solution of sodium chloride (brine), it is electrolysed and hydrogen gas is released at the cathode while chlorine gas is released at the anode.
• This method is used for production of chlorine gas. In this method an important basic compound NaOH is formed in the cell.

2NaCl + 2H₂O → 2NaOH + Cl₂ ↑ + H₂ ↑

• When salt is heated to a high temperature (about 800 °C), it melts. This is called the fused state of the salt.
• When fused salt is electrolysed, chlorine gas is released at the anode and liquid sodium metal, at the cathode.

Some of the substances we use in our day to day life and the purpose of using them are as follows:

Toothpaste : for cleaning teeth and maintaining hygienic conditions of mouth.

Soap : for bathing and maintaining hygienic conditions of body.

Natural and artificial fibers : we wear them as clothes to protect our body and many other purposes.

Washing powder: for cleaning clothes. Vegetables, fruits and food grains : they provide us with necessary vitamins, minerals and carbohydrates required for proper functioning of body.

Water : very important for our survival and many other functions of day to day life.

Metals : for making buildings, bridges, roads, vehicles, trains, ships, airplanes, utensils etc.

Acids, bases and salts : used for various purposes, for example, Sodium chloride which is used as common salt, a very necessary ingredient of our daily food without which our food is tasteless.

• A protective layer is formed naturally on the surface of aluminium metal by reaction with oxygen in air.
• In the anodizing process, this layer can be made of the desired thickness. 
• Anodizing is done by electrolysis. 
• Dilute sulphuric acid is taken in the electrolytic cell and the aluminium article is dipped in it as the anode. 
• When an electric current is passed, hydrogen gas is released at the cathode and oxygen gas at the anode.
• A reaction with oxygen occurs and a layer of hydrated aluminium oxide is formed on the anode, i.e. the aluminium article.
• This layer can be made attractive by adding colour in the cell during electrolysis.

• Inorganic substances occur naturally in the form of salts rather than acids or bases.
• The ionic compounds which do not contain H+ and OH ions and contain only one kind of cation and anion are called simple salts.
• For example, Na₂SO₄ , K₃PO₄ ,CaCl₂.
• The sea is said to be a rich source of salts. In fact, the sea is a rich source of several salts of various elements such as chlorine, sodium, magnesium, potassium, calcium, bromine.
• The important salts found in sea water are sodium chloride, magnesium chloride, magnesium sulphate, potassium chloride, calcium carbonate and magnesium bromide.

(D) Delhi and Ajmer

(B) Mahmud Ghazni

• Luminous colours are used to decorate ceramic tiles, utensils, plates, etc. 
• Earlier uranium oxide was used in these paints.

• When an electric current is passed through a saturated solution of sodium chloride (brine) it is electrolysed and hydrogen gas is released at the cathode while chlorine gas is released at the anode. 
• This method is used for production of chlorine gas. In this method an important basic compound NaOH is formed in the cell. 
• Chemical reaction

2NaCl + 2H₂O → 2NaOH + Cl₂ ↑ + H₂ ↑

• When salt is heated to a high temperature (about 800°C), it melts. This is called the fused state of the salt.

• Alum (Potash alum – K₂SO₄.Al₂ (SO₄)₃.24H₂O)
• Borax (Na₂B₄O₇.10H₂O)
• Epsom salt (Magnesium sulphate MgSO₄.7H₂O)
• Barium chloride (BaCl₂.2H₂O)
• Sodium sulphate (Glauber’s salt Na₂SO₄.10H₂O)

• The ionic compounds which do not contain H+ and OH ions and contain only one kind of cation and anion are called simple salts. 
• For example, Na₂SO₄, K₃PO₄, CaCl₂ .
• The sea is said to be a rich source of salts of various elements such as chlorine, sodium, magnesium, potassium, calcium, bromine.
• The important salts found in sea water are: 

(a) Sodium chloride 

(b) Magnesium chloride 

(c) Magnesium sulphate 

(d) Potassium chloride 

(e) Calcium carbonate 

(f) Magnesium bromide

Correct answer is:

a. 10 

b. Sodium bicarbonate 

c. Lodine -123 

d. Polytetra fluoroethylene (C₂F₄)_n

• Ceramic is a heat resistant substance formed by kneading an inorganic substance in water and then shaping it and hardening it by heating.
• Pots made by a potter, Mangalore roofing tiles, construction bricks, pottery, terracotta articles are some examples of common ceramic articles that we see around.

(A) Raja Tarangini

(i) Each shuttle is covered by more than 24,000 of the six- by six-inch advance ceramic tiles. This tiles withstand high temperatures without decomposing. They are brittle, water-resistant and electrical insulator. Most of the tiles are made of silica fibres, which are produced from high-grade sand (SiO₂).

(ii) Silica is an excellent insulator because it transports heat slowly. When the outer portion of a tile gets hot, the heat takes a long time to work its way down through the rest of the tile to the shuttle’s skin. The tiles keep the orbiter’s aluminium skin at 350 degrees or less.

(iii) The silica fibers are mixed with water and chemicals, and the mixture is poured into molds, which are zapped in microwave ovens at 2,350°C to fuse the silica fibres. Tiles are too brittle to attach to the orbiter directly.

(iv) The shuttle’s skin contracts slightly while in orbit, then expands during re-entry. 

(v) In addition, the stresses of launch and re-entry cause the skin to flex and bend. Such motions could easily crack the tiles or shake them off. To keep them in place, workers glue the tiles to flexible felt-like pads, then glue the pads to the orbiter.

(a) Artificial dye: 

• Dyeing hair can have adverse effects like hair fall, damage to hair texture, burning of skin, adverse effect on eyes, etc. 
• Lipstick contains a dye named carmine. It does not affect lips but causes stomach disorders. 
• Excessive use of plants for making natural dyes results in deterioration of the environment.

(b) Artificial food colour:

• Food colours added to pickles, jams and sauces contain small quantities of lead and mercury. These can be harmful for those who consume these products on a regular basis. 
• Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

(c) Radioactive substances :

• The central nervous system is affected by radioactive radiations. 
• Hereditary defects are generated by bombardment of radiation on D.N.A in the body. 
• Radioactive radiation can penetrate the skin, and causes diseases like skin cancer, leukemia. 
• The radioactive pollutants created due to explosions enter the body through air and it is difficult to control them. 
• The radioactive pollutants released in the sea enter the bodies of fishes and through them enter the human body. 
• The radioactive paint on the watch can cause cancer.
• The radioactive isotopes strontium-90 can enter the body through plants, fruits, flowers, cereals, milk, etc. and cause diseases like bone cancer, leukemia.

(d) Deodorant:

• Aluminium – Zirconium compounds are the most harmful chemicals in the deodorant. Disorders like headache, asthma, respiratory disorders, heart disease are likely to occur without our knowledge. 
• There is a possibility of various skin disorders and also skin cancer due to the aluminium chlorohydrates.

(A) common people

(D) all the above

(A) Roadways

Rulers belonging to the GurjaraPratihara, Rashtrakuta, and Pala dynasties fought for control over Kanauj. These three were the parties involved in the ‘tripartite struggle’.

(a) Artificial food colour and substances in them. 

• Food colours are mixed in most soft drinks and foodstuffs available in the market. 
• These food colours are in the form of powders, gels and pastes. 
• Food colours are used in domestic as well as commercial products. 
• Certain colours and essences are added to ice cream, ice candies, sauce, fruit juices, cold drinks, pickles, jams and jelly. 
• Food colours are often found to be added to packaged meat (chicken, mutton), chilli powder, turmeric, sweets and other similar substances so as to give them a good colour. 
• Tetrazene, sunset yellow are artificial food colours used extensively.

(b) Harmful effects of artificial food colours 

1. Food colours added to pickles, jam and sauce contain small quantities of lead and mercury. These can be harmful for those who consume these products on a regular basis. 

2. Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

• We regularly use artificial colours on Rang Panchami. 
• The red colour used on Rang Panchami is very dangerous.
• It contains a high proportion of mercury in it. 
• This poses risks like blindness, skin cancer, asthma, itching of the skin, permanent blocking of sweat pores, etc. 
• Therefore, it is necessary that artificial colours are used cautiously.

Answer is (C) 7th

(C) Road Safety Week

Students: Good Morning Sir. 

Constable: Good morning students. 

Students: Sir Now a days the majority of people lost their lives due to road accidents. Is there any programmes implemented by the government to control the accidents?

Constable: Yes children. In that part, only government conduct Road Safety Week every year.

Students: Sir, why do we celebrate Road Safety Week.

Constable: To control road accidents. Students: Sir, which activities are included in the road safety week. 

Constable: On this occasion, they give guidelines to the people to follow traffic rules.

Students: Is there any other programmes run by the A.P government about safety? 

Constable: Yes, children. Governmentrun companies such as the A.P.S.R.T.C conduct awareness campaigns among drivers and give them the training to drive safely. 

Students: Is there any special programmes for school and college students about road safety. 

Constable: They also go to schools and colleges to organise essay writing, debate, and other competitions for students and encourage them to travel safely following traffic rules. 

Students: Thank you, sir, you give valuable information about road safety week and we also take responsibility to follow the road rules and make others also follow the rules and try to reduce road accidents.

(A) First week of January

Edison promised to give Americans electric light in one year: False.

Even in his childhood Edison loved to do experiments: True.

Edison succeeded in inventing the electric light after about twelve hundred experiments.

As we know that to get information about a subject is science and putting that information to practice is an art, so in the present case, it can be said that the study of M.B.B.S. and M.S. is science and working as an eye-surgeon is an art.

Yes Mr Sourabh is at fault. He is avoiding the social objective of management.

There is need of rethinking on two issues:

i. Establishing Chemical Plant near a residential colony and

ii. Giving Charity.

The sound absorbing materials are used in :

• School, cinema hall, concert hall, houses or places where quality of sound is important. 
• In the absence of sound absorbing material the sound will undergo multiple reflection causing reverberation of sound.

1. Dimensions: The distance between opposite walls in a classroom must be less than 17.2 m so that the reflected sound returns to the observer within 0.1 s. 

2. Shape: The classrooms should have curved ceilings and walls so that the reflected sound is directed towards the observer instantly within 0.1 s.

• No, the distance from the source of sound to the reflecting surface will not be the same at all temperatures. 
• Velocity of sound is directly proportional to the square root of temperature. 
• One of the conditions of echo is that the time interval between the original and reflected sound should be more than 0.1 sec. 
• So if the temperature increases, the velocity of sound increases and the reflected sound reaches in less than 0.1 sec. 
• So for echo to be heard the distance between the observer and the reflecting surface has to increase.

Huntington’s disease is an autosomal dominant disorder and sickle-cell anaemia is an autosomal recessive disorder.

Tapetum is the innermost layer of microsporangium. It provides nourishment to the developing pollen grains. During micro sporogenesis, the cells of tapetum produce various enzymes, hormones, amino acids and other nutritious material required for the development of pollen grain. It also produces the exine layer of the pollen grains, which is composed of the sporopollenin.

Emasculation is the process of removing anthers from bisexual flowers without affecting the female reproductive part (pistil). Emasculation is performed by plant breeders in bisexual flowers to obtain the desired variety of a plant by crossing a particular plant with the desired pollen grain. After removing the anthers, the flowers are covered with a bag before they open. This ensures that the flower is pollinated by pollen grains obtained from desirable varieties only. Later, the mature, viable and stored pollen grains are dusted on the bagged stigma by breeders to allow artificial pollination to take place and obtain the desired plant variety.

Parthenocarpy is the process of developing fruits without involving the process of fertilization or seed formation. Therefore the seedless varieties of economically important fruits such as orange, lemon, grapes etc. are produced using this technique. This technique involves inducing fruit formation by the application of plant growth hormone such as auxins.

Double fertilization leads to the development of triploid endosperm which provides nourishment to the developing healthy seed and this triploid endosperm compensates for the extreme reduction of female gametophyte in angiosperms.

i – d,

ii – c, 

iii – a

The fruits which develop from parts other than ripened ovary are called false fruits.
Eg: fruits of apple and pear develop from fleshy thalamus.

Micropyle facilitates the entry of oxygen and water into the seed during germination.

Inbreeding is necessary if we want to evolve a pure line in any animal / plant.

Seed dormancy is the condition of the seed when it fails to germinate even though the environmental conditions are favourable for active growth.
Two advantages of dormancy:

• It help the seed to disseminate in time and space in order to achieve maximum cooperative environment for the survival of species.
• To ensure the successful seed germination under most favourable condition.

No residual endosperm, retain endosperm, residual persistent nucellus, fruit wall,state of inactivity.

Water content is reduced seeds become dry, metabolic activity slows down,state of inactivity, storage of seeds –food throughout the year / raise crop in next season.

1. Pollen release and stigma receptivity are not at the same time.

2. Another and stigma are placed at different positions.

3. Self-incompatibility.

4. Production of unisexual flowers.

Wind-large amount,light non-sticky,well exposed stamens,feathery stigma Water– mucilaginous covering long ribbon –like Insect-large colourful,fragrant, nectar.