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Disease: 

• Filariasis 

• Rabies 

• Chickenpox

Causative agent: 

• Wuchereria bancrofti 

• rabies virus 

• Vpricella zoster

Symptom: 

• the inflammatory thickness of the wall of lymphatic vessel. 

• Severe headache, high fever, severe and painful spasm of muscles 

• Skin eruption occurs as small red papules which grows out into pustules

The process of crossing two genetically different plants to obtain a progeny having a combination of desirable characteristics is called Hybridisation. It may be interspecific or intraspecific or intergeneric.

Procedure of hybridisation:

1. First of all we select the plants with desirable traits. 

2. In bisexual plants anthers are removed from the stamens (emasculation) to avoid self-pollination. In unisexual plants and in self-sterile bisexual plants emasculation is not required. Male sterillity has been reported in many plants such as wheat, maize, sorghum, barley, sunflower etc.

3. The emasculated flower is immediately enclosed within polythene bag to prevent the pollination from unwanted plants. This process is called bagging. 

4. The emasculated and bagged flowers must be tagged by writing every step with date and time. The bagging and pollination is incomplete without tagging. 

5. During artificial pollination, the mature and viable pollen grains are collected from the male parent and the pollen grains from the bag are dusted over the stigma. The bag is replaced immediately over artificially pollinated stigma. 

6. Hybrid. Seeds of the cross are sown to raise the F (first filial) generation progeny. The breeding of ‘hybrid corn’ is an important example of hybridization. It is produced by crossing two inbred or homozygous lines of maize. The inbred lines aree true breeding and highly uniform.

(i) Amoebiasis: 

Causative agent: Entamoeba histolytica (Protozoan). 

Preventive measure : Proper sanitary conditions, proper coverage of eatables, proper washing of fruits and vegetables before eating.

(ii) Rabies : 

Causative agent: Rabies virus (RNA virus) infection by bite of rabid, dog, monkeys, cats etc.

Preventive measure: Isolation and killing of rabid dogs. Immunization of domestic cats and dogs, injection of vaccine to person bitten by dog.

(iii) Pneumonia : 

Causative agent: Diplococcus pneumoniae (bacteria). 

^{Preventive measure :} Isolation of infected persons.

Manure is a partially decayed organic wastes that increase the soil fertility. They supply all essential elements required by crop plants. They also improve the physical conditions of soil by preventing erosion and leaching and increase the water holding capacity of the soil.

Manure are of two types 

(i) Green Manure and 

(ii) Farmyard Manure

(i) Green Manure : They are obtained by cultivating quick growing leguminous and non- leguminous crops. The crop is ploughed when the plants are about one foot height. The green manure crop supplies the organic as well as inorganic components to the soil. It also provides a protective action against erosion and leaching e.g. Dhaincha (Sesbania aculeata) cluster beans (Cymopsis tetragonoloba), sun-hemp (Crotolaria juncea), cowpea (Vigna sinensis) are some of leguminous crops commonly used as greeen manures.

(ii) Farmyard Manure: It is the most valuable decayed organic matter commonly applied to the soil. It is obtained by the partial decay of animal dung, farm refuse and crop residues. These materials are stored in heaps in a pit and kept moist. The manure becomes ready after 4-5 months. The manure is dark coloured, amorphous and rich in humus. Manure enriches the soil with organic substances and releases mineral elements in the soil. Residue of gobar gas plant is a kind of farmyard manure.

DDT resistance of mosquitoes to pesticides: Earlier DDT (dichloro-diphenyl trichloroethane) has been supposed to be the best pesticide for controlling the population of the mosquitoes which spread malaria. Under the National Malaria Eradication Programme, DDT was extensively sprayed to kill the mosquitoes. This made the mosquitoes to adapt and become resistance to the DDT and other pesticides. This can be explained on the basis of natural selection.

Before the discovery of DDT, the mosquito population had more DDT-sensitive and less DDT- resistant mosquitoes. As DDT was not being used, the DDT resistant remained undetected, unidentified and dominated by DDT sensitive mosquitoes. But when the use of DDT as an insecticide started, the DDT resistant mosquitoes had a competitive survival mosquito with advantage over their counter parts. Then only with the resistant genotypes were able to survive and reproduce. The DDT resistant characteristic strain multiplied and spread over more and more members of the population. Gradually their number in the population increased while the DDT sensitive type were finally eliminated, making the mosquito population resistant to DDT.

Homologous organs: 

1. They have a common origin and structure. 

2. They perform different functions. 

3. Eg. Forelimbs of vertebrates.

Analogous organs: 

1. They have a different origin and structure. 

2. They perform same function. 

3. Eg. Wings of insect and bird.

Lanthanide contraction

It is the slow or gradual decrease in the sizes of atoms or tri positive ions of lanthanide as we move from left to right along the lanthanides. General electronic configuration of inner transition elements is

[Xe]₅₄ 4f^1-14 5d^0-1 6s² – For lanthanides

[Rn]₈₆ 5f^1-14 6d^0-1 7s² – For actinides

Potassium hexacyanoferrate (II) does not give ferrous (Fe²⁺⁾ ions in solution because it is complex and Fe²⁺ ions are in the coordination sphere and form coordinate bonds with cyanide, CN^– ligands.

1. SO₂ as an oxidising agent

2Mg + SO₂ → 2MgO + S (Burning)

2. SO₂ as a reducing agent

SO₂ + Br₂ + 2H₂O → H₂SO₄ + 2HBr

(a) Ore of zinc is zinc blende (ZnS).

(b) It is concentrated by Froth floatation process.

(c) Concentrated ore is changed into oxide by heating ZnS in excess of air.

2ZnS + 3O₂ + 800 °C → 2ZnO + 2SO₂

Oxides of highly active metals like potassium, sodium, calcium, magnesium and aluminium have great affinity towards oxygen and so cannot be reduced by carbon or carbon monoxide or hydrogen.

Metals in the middle of activity series (iron, zinc, lead, copper) are moderately reactive and are not found in oxide form. These are found in nature as sulphides or carbonate. These are first converted into oxides and can be reduced by C, CO or H₂

ZnO + C + 400°c → Zn + CO

PbO + CO + heat → Pb + CO₂

Metals low in the activity series is very less reactive and oxides of these metals are reduced to metals by heating alone.

River Satluj and River Kali

(a) A = Conc. Sulphuric acid

B = potassium nitrate

C = nitric acid

(b) Nitric acid undergoes decomposition as follows:

4HNO₃ + heat → 4NO₂ +2H₂O +O₂

(c) Copper is oxidized by concentrated nitric acid:

Cu + 4HNO₃ →Cu(NO₃)₂ + 2H₂O +2NO₂

The chemical equation:

HNO₃ ⇌  H⁺ + NO₃^-

When ammonium nitrate is heated the products formed are nitrous oxide and steam.

The noble metals such as gold and platinum do not corrode easily.

Due to presence of free impaired electrons occupying anionic vacancies a magnetic moment results by the spin of electron in a particular direction. The ionic crystals with F-centres, therefore, show paramagnetic behaviour.

The given equation is : 

2C₂H₆ + 7O₂ ----> 4CO₂ + 6H₂O

(i) So, according to above equation, 2 V (volume) of ethane reacts to give 4 V of carbon dioxide. 

So, 300 cc of ethane would give 600 cc of carbon dioxide. 

(ii) Also, 2 V(volumes) of ethane reacts with 7 V of oxygen. 

300 cc of ethane is 2 V, so oxygen required for 300 cc of ethane is 

300 x 7 /2 =1050 cc 

The remaining oxygen would be :

125O cc - 1050 cc = 200 cc

By quantization of charge, we mean that charge is not continuous but exists in discrete magnitude. The minimum charge is e, the charge on the electron. The charge on a body is always an integral multiple of this minimum charge i.e., Q = ± Ne, where N is an integer

(C) They are insoluble in water.

(C) They are insoluble in water 

Nitrogen gas can be obtained by eating Ammonium nitrite.

Because across a period atomic sice decreases and nuclear charge increases so, more energy is required to remove a valence electron. 

(i) From equation:

2 x 98 g of sulphuric acid oxidises 12g of carbon

∴  49 g of sulphuric acid will oxidise = \(\frac{12\times49}{2\times98}\)

                                                     = 3g of C.

(ii) From equation:

2 x 98 of sulphuric acid liberates 2 x 22.4 l of SO₂.

  49 g of sulphuric acid will liberate = \(\frac{2\times22.4\times49}{2\times98}\)

                                               = 11.2 l of SO₂.

Alkali metals have low value of ionisation potential so they can lose electron easily so they act as good reducing agent.

Because they have low ionization potential.

Alkali metals are good reducing agents because alkali metals have ns¹ outer electron configuration and they achieve the nearest stable configuration by losing one electron, hence they have a great tendency to loose electrons or get oxidized therefore, they are good reducing agents.

Because across a period, atomic size decreases and nuclear charge increases, so more energy is required to remove a valence electron.

(B) Oxidising agent

1. NO₃ ^– (Nitrate ion) 

2. Cl^– (Chloride ion) 

3. CO₃ ^{– –} (Carbonate ion) 

4. SO₄ ^{– –} (Sulphate ion)

Because they have low ionization potential.

(a) When Sodium hydrogen carbonate is added to nitric acid sodium nitrate, carbon dioxide and water is formed.

NaHCO₃ + HNO₃ → NaNO₃ + H₂O + CO₂

(b) When Cupric oxide reacts with dilute nitric acid, it forms Copper nitrate.

CuO + 2HNO₃ → Cu(NO₃)₂ + H₂O

(c) Zinc reacts with nitric acid to form Zinc nitrate, nitric oxide and water.

3 Zn + 8HNO₃ → 3Zn(NO₃)₂ + 4H₂O + 2NO

(d) 4HNO₃ → 2H₂O + 4NO₂ + O₂

Due to the formation of an extremely thin layer of insoluble iron oxide which stops the reaction.

Due to the formation of an extremely thin layer of insoluble iron oxide which stops the reaction.

1. Cu²⁺ 

2. Pt 

3. Cu²⁺/Nil 

4. Na⁺ 

5. Ag

1. Hydrogen 

2. Nitrogen 

3. Sulphur dioxide 

4. Nitrogen dioxide 

5. Hydrogen sulphide

Because quick lime is basic in nature and combines with moist hydrogen chloride gas forming calcium chloride.

1. Cone. HNO₃ being a strong oxidising agent oxidises iron, forming a layer that makes iron non reactive or passive. 

2. Aqueous solution of sodium chloride contains mobile ions like Na⁺ , Cl^– , H⁺ , OH^– , H₃O⁺ etc.

so they conduct electricity.

3. Atomic size decreases and nuclear charges increases as we move from left to right in a period so energy required to remove one electron from the valence shell increases from left to right thus ionisation potential increases.

4. Alkali metals readily lose electrons from their valence shell and get oxidised. So they behave as good reducing agents. 

5. Hydrogen chloride is acidic whereas quick lime is basic. So they will react with each other hence quick lime can not be used to dry hydrogen chloride.

(i) (B) Dehydrating agent 

(ii) (D) Oxidising agent

(iii) (C) Non-volatile acid 

(iv) (A) Dilute acid 

(v) (D) oxidising agent

(i) B – Dehydrating agent. 

(ii) D – Oxidising agent 

(iii) C – Non-volatile acid 

(iv) A – Dilute acid. 

(v) D – Oxidising agent

1. Cryolite: To reduce the melting point of Alumina and increase the conductivity of solution.

2. Sodium hydroxide: for purification of bauxite ore as a leaching agent.

3. Graphite: As anode and make the reduction of Al₂O₃ easier.

(1) Cryolite acts as a solvent for the electrolytic mixture as it lowers the fusion temperature from 2050^oC to 950^oC and enhances conductivity 

(2) Sodium hydroxide is used to remove insoluble impurities from the ore. When bauxite ore is treated with sodium hydroxide, it dissolves and forms sodium aluminate leaving behind insoluble impurities called red mud (consists of ferric oxide, sand etc.) 

(3) Graphite is used as an electrode in the extraction of aluminium because it has a very high melting point and is a good conductor of electricity.

1. Ammonium nitrate is a highly explosive substance and can not be heated. 

2. Quicklime/CaO. 

3. By downward displacement of air or upward delivery as it is lighter than air. 

4. Ammonia is highly soluble in water so it cannot be collected over water.

1. Aluminium

2. Gold 

3. Sodium

(i)  The loss of money from De Levis’s room at Meldon Court is being talked about in the extract. Winsor is suspecting that somebody must have seen De Levis getting money from Kent man and must have followed him to his room. Winsor thinks that someone must have entered the room through the open window or must have had a skeleton key to the room.

(ii)  Treisure is Winsor’s butler who has been with him for a long time. Winsor wants to make some enquiry regarding the where abouts of the servants in the house from Treisure and that’s why he has been called. Winsor asked the name of De Levis’s valet and at what time had he gone to bed. He was also asked about the character of the valet, Robert.

(iii)  Treisure is a silent, grave man who appears like a supernatural being. Winsor Trusts Treisure as he has been working for him for years. He also seems to value his opinion as proved in the questions regarding the valet.

(iv)  De Levis doesn’t trust anybody in the house. He views Treisure also with suspicion and this is the reason why he gives him a hard look. Winsor trusts Treisure and doesn’t like De Levis’s suspicious look at the butler, moreover, De Levis is a Jew and he suspecting the English butler is resented by Winsor.

(v)  Treisure was called to get information regarding the valet of De Levis. Winsor was making enquiry about the loss of money from De Levis’s room. Treisure, being an old servant at Meldon Court, knows a lot about the people working there. He gives the information that Robert has been the valet and he was dismissed at eleven in the night. He is also asked whether he had seen any stranger loitering about. One can say that he has been able to serve the purpose for which he has been called.

(i) Edward Graviter is a solicitor. Jacob Twisden is the senior solicitor. They both are professional partners. They are discussing the case of the stolen money of Mr. De Levis stealing case. Considering upon Gilman’s anonymous admission of theft and the happening of new prosecution Graviter feels that he will lose the case. 

(ii) The latest evidence was that they got the note which was stolen from De Levis. Graviter had got it from an Italian wine merchant Ricardos who said he got it from Dancy when he paid his daughter before he left her to get married. 

(iii) Twisden is quite loyal to his profession as he is quite bound to his professional duty, against good faith of solicitors he can hang deal how big it be. He also propose to inform Sir Frederic about Gilman’s anonymous admission. Twisden ask Graviter to see Dancy at once and to make him a call. 

(iv) Twisden advices Dancy to immediately go to Morocco and to further slip on from there. The purpose of De Levis calling on Twisden is to inform him that he has overheard that a warrant is going to be issued and he has no roll or support in it. 

(v) Mabel shows her loyalty to her husband by encouraging him to go to Morocco and by promising him to stick with him for ever sleep on loving him with same intensity and she will wait until he return from prison. The most appealing character of Dancy is that he is an honest creditable debtor. In the end Dancy commits suicide with a pistol.

(i) Charles Winsor was the owner of Meldon Court near New Market. Here Margaret means that they now have a clue as Winsor had said that if there is rain there should be footprints. The scene is taking place in Charles Winsor’s dressing room at Meldon Court. 

(ii) Canynge says to Winsor that they must be careful with the inspector fellow. He may have suspicion on any house member. 

Winsor surprises and further says that all this will be disagreeable and even humorous to others. 

(iii) Treisure enters the room. He bad been asked to call Robert and to check if the stable ladder had been moved. 

(iv) De Levis is young and rich Jew in the Meldon Court. He Suspects upon Ronald Dancy one of the guest of Charles Winsor. Canynge also has suspected him as his sleeves were quite damp as if by rain wet. 

(v) De Levis had a large amount of money on him that day in exchange of Rosemary filly, a horse, which Ronny gifted him eqrlier. He sold the horse to Kentman, the bookie, who paid him in cash.

(i) Mr. Gilman is the head of Gilman’s department stores. He want to see Mr. Twisden so that he can tell the truth of the notes and save Dancy from the case. 

(ii) Mr. Gilman told Twisden that he was following Dancy’s case. So he read in the ” newspaper about the numbers of the notes and he realises that those number notes were given by him to his customer Mr. Ricardos. So he decided to come along with Mr. Ricardos at the office of Twisden to tell the truth. 

(iii) Mr. Ricardos told Twisden that he got those notes from captain Dancy. He also told that notes were given as a compensation to his daughter by Dancy, who was very intimate with her and wanted to keep this as a secret. 

(iv) Mr. Twisden decided to meet Sir Fredrick so that he can reveal the true facts to him. But, Twisden came to know that Sir Fredrick has gone to Brighton for the might. So, he also decided to go to Brigthon to meet him. 

While leaving to Brighton, Twisden asked Graviter to go at Ricardos address in Putney to check whether he has a daughter or not. Twisden also tells Graviter that if he found someone there than he should not say anything to her and invent some excuse. 

(v) Mabel was noblest wife of her husband Dancy. When truth revealed about the theft of notes and she came to know that court has accused Dancy for this, she was shocked and saddened that if she would had gone to Africa three months ago then this would have not happened. Till the end of the play Mable has shown loyalty to her husband. She knows that her husband had married her without telling her about his earlier love affair. She knows that he has stolen money and has been deceiving her all along. She knows that he may be sent to prison. Even then her loyalty remains firm as a rock.

Temperature of the surroundings starts falling when the ice starts melting because every 1 gm of ice requires 336 J to convert it into water at 0°C so it extracts a great amount of heat from the atmosphere.

Total investment = Rs 22,500 

Face value of a share = Rs 50 

Market value of a share = Rs (50 – 10% of 50) = Rs (50 – 5) = Rs 45 

∴ No. of shares purchased = 22500/45 = 500 

Annual dividend per share = 12 % of 50 = (12/100) x 50 = Rs 6 

Total annual dividend = Rs 6 × 500 = Rs 3000 

Rate of return = (3000/22500) × 100 = 13.3 % 

= 13% (Nearest whole number) 

Hence, number of shares purchased are 500, total annual dividend is Rs 3000 and rate of return on investment is nearly 13 % p. a.