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There are three type of biofertilizers:

(i) bacteria

(ii) fungi

(iii) cyanobacteria

Biofertilizers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilizer are bacteria, fungi and cynobacteria. Rhizobium fix atmospheric nitrogen into organic forms through nodules on the root of leguminous plants, which is used by the plant as nutrient. Other bacteria can fix atmospheric nitrogen while free living in the soil (example Azospirillium and Azotobacter), thus enriching the nitrogen content of the soil. Fungi are also known to form symbiotic associations with plants (i.e., Mycorrhiza). 

Cyanobacteria are autotropic microbes widely distributed in aquatic and terrestrial environments many of which can fix atmospheric nitrogen. e.g., Anabaena, Nostoc etc. In paddy fields, Cyanobacteria serve as an important biofertilizer. Blue green algae also acid organic matter to the soil and increase the fertility.

Correct Answer is: C) 1:2:1 

Appearance of new phenotypes or intermediate phenotypes, other than parental phenotypes in progeny is incomplete dominance. In this, In the F2 generation, 1 red flowered plants(RR), two pink flowered plants(Rr), 1 white flowered plants(rr) are formed. So, the phenotypic and genotypic ratio is 1:2:1.

Plants produce through photosynthesis, which is possible only when sunlight is available as a source of energy.  Many species of small plants, growing in forests are adopted to photosynthesis optinally under very low conditions because they are constantly over shadowed by tall, canopied trees. Many plants are also dependent on sunlight to meet their photoperiodic requirement for flowering. The availability of light on land is closely linked with that of temperature since the sun the source for both.  

Correct Answer is: (A) Soil

Soil water holding capacity is a term that all farms should know to optimize crop production. Simply defined soil water holding capacity is the amount of water that a given soil can hold for crop use. 

Field capacity is the point where the soil water holding capacity has reached its maximum for the entire field.

It can be done by:

(i) Increasing the height of the tower.

(ii) Increasing the height of the receiving antenna so that it may directly intercept the signal from the transmitting antenna.

Rate of reaction:- It is defined as, the rate at which the concentration of a reactant changes with time. The rate at which a reaction proceeds can be followed by measuring the concentration at either a reactant change during a small interval of time dt, then the rate of reaction is represented by dx/dt. If on other hand  dc represents the concentration of the reactant left behind after a short interval of time dt. then the rate of reaction is represented by dc/dt. The negative sign implies that the concentration of the reactants decreases with time or rate of reaction decreases with time.

Unit of rate:-

∵ Rate of reaction = {Concentration}/{time}

= {mol/litre}/{second}

Unit of rate = mol lit^-1 sec^-1

Factors affecting the rate of reaction:- Following are the factors which affect the rate of reaction-

(i) Concentration of reactants

(ii) Temperature

(iii) Nature of reactants

(iv) Catalyst

(v) Surface area of reactants

All above factors affect the rate of reaction.

Correct Answer is: (B) Mortality 

Mortality rate is found out number of deaths in exact population scaled to the size of the population as per the unit of the time. But now 12.4 % of death population ageing with no trouble and risk of it.

Unit cell:- Unit cells is the smallest portion of a crystal lattice which, when repeated in different directions generates the entire to lattice.

A unit cell is characterised by (i) its dimensions along the three edges, a, b and c. These edges may or may not be mutually perpendicular.

(ii) Angle between the edges α (betwen b and c), β (between a and c) and γ (between a and b).

Thus a unit cell is characterised by six parameters: a, b, c, α, β and γ unit cells can be broadly divided into two categories- primitive and centred unit cells.

(i) Primitive unit cells: When constituent particles are present only on the corner position of a unit cells, it is called as primitive unit cell.

(ii) Centred unit cells: When a unit cells contains one or more constituent particles present at positions other that corners in addition to those at corners it is called a centred unit cell. Centred unit cells are of three types:

(a) Body centred unit cells:- Such a unit cells contains one constituent particle (atom, molecules or ion) at this body centred besides to ones that are at corners.

(b) Face centred unit cells:- Such a unit cell containing one constituent particles present at the centre of its each face, besides the one that are at its corners.

(c) End centred unit cells:- In such a unit cell one constituent particles is present at the centre of any two opposite faces besides the one present at its corners.

In all there are seven types of primitive unit cells. They are cubic, tetragonal, orthorhombic, hexagonal, rhombohedral of trigonal monoclinic and triclinic.

Physical adsorption:-

1. Enthalpy of adsorption usually is the order of 20-40 kJ mol^-1.

2. Moles of adsorbate and adsorbent are held by Van der Waals interactions.

3. It usually takes place at low temperature and decreases with increasing temperature.

4. It is not very specific i.e., all gases are adsorbed at all solids to some extent.

5. Multi-molecular layers may be formed on the adsorbent.

6. It does not require any activation energy.

7. The amount of adsorbed in related to the case of liquefaction of the gas.

8. It is reversible in nature.

Chemical adsorption:-

1. Enthalpy of adsorption is of the order 40-400 kJ mol^-1

2. Molecules of adsorbate and adsorbent are held by chemical bonds.

3. It takes place are relatively high temperatures.

4. It is highly specific and takes place when there is some possibility of compound formation between the adsorbent molecules.

5. Usually mono-molecular layer is formed on the adsorbent.

6. It requires activation energy.

7. There is no such correlation.

8. It is irreversible in nature.

Physical adsorption:- When it particles of the adsorbate and held to the surface of the adsorbent by the weak forces such as Van der Waals force the adsorption is called physical adsorption of physisorption.

Chemical adsorption:- When the molecular of the adsorbate are held to the surface of adsorbent by the chemical forces, the adsorption is called chemical adsorption. In case a chemical reaction occurs between the adsorbed molecules and the molecules or atoms of adsorbent. It is also known as chemisorption.

Adsorption:-

The existence of a substance at the surface in different concentration than in the adjoining bulk is called adsorption.

Ex. (i) water vapours on silica gel

(ii) H₂, O₂, NH₃ on activated charcoal

Potassium permagnate is prepared from pyrulsite first of all. Pyrulusite is oxidised in alkaline medium in the presence of air or oxidising agent like KNO₃ to give potassium magnate, which undergoes disproportion reaction in acidic medium to give potassium permagnate.

2MnO₂ + 4KOH + O₂ → 2K2MnO₄ + 2H₂O

3MnO₄^- + 4H⁺ → 2MnO₄ + MnO₂ + 2H₂O

(c) All the lanthanons are much more reactive than aluminium.

As we move from La to Lu , their metallic behaviour because almost similar to that of aluminium.

Isoelectronic species:- Atoms and ions which contains the same number of electrons are called isoelectronic species.

(i) F^- has the electronic configuration,

F        +       e^-       →        F^-

2,7                                  2,8

             (Total of 10 electrons)

So any species having 10 electrons would be isoelectronic with F^-. From the periodic table, the possible ions/atoms are,

Ne(10) 2,8    [∵ Na → Na⁺ + e^-]

Na⁺(10) 2,8    2,8,1      2,8

Therefore, Ne and Na⁺ are isoelectronic with F^-

(ii) Ar (atomic no. = 18) has an electronic configuration (1s² 2s² 2p⁶ 3s² 3p⁶ (18 electrons). So, any atom or ion having 18 electrons with the same distribution as shown by Ar would be isoelectronic with it. from the periodic table, the elements on either side of the Ar are Cl (17) and K (19). These atoms can acquire Ar structure by the reaction

Cl           +        e^-      →         Cl^-

(2,8,7)                                 (2,8,8)

                            (Total of 8 electrons)

and K     →       K⁺    +     e^-

  (2,8,8,1)       (2,8,8)

Therefore, Cl^- and K⁺ are isoelectronic with Ar

(iii) Mg²⁺ has the electronic configuration

Mg        →         Mg²⁺      +      2e^-

(2,8,2)                (2,8)

Thus all the atoms and ions having 2,8 configuration are isoelectronic with Mg²⁺. From the periodic table, the elements on either side of magnesium are Ne(10) and Na(11). Na can acquire Mg²⁺ structure by losing electronic as:

Na              →             Na⁺     +      e^-

(2,8,1)                       (2,8)

Al             →          Al³⁺      +       3e^-

(2,8,3)                  (2,8)

Therefore, Ne and Na⁺ and Al³⁺ are isoelectronic with Mg²⁺

(iv) Rb⁺ is obtained from Rb (atomic no. = 37) by losing one electron

Rb           →           Rb⁺      +      e^-

(2,8,18,8,1)       (2,8,18,8)

Thus, the atoms or ions having 2,8,18,8 configurations are isoelectronic with Rb⁺. From the periodic table, the following species have (2,8,18,8) configuration:

(a) Kr      →      (2,8,18,8)

(b) Br         +       e^-       →       Br^-

(2,8,18,1)                             (2,8,18,8)

(c) Sr        →           Sr²⁺       +       2e^-

(2,8,18,8,2)                    (2,8,18,8)

Thus, Kr, Br^- and Sr²⁺ are isoelectronic with Rb⁺

(a) Chemical Equation— A chemical equation is the symbolic representation of a chemical reaction using the symbols and the formulae of the substances involved in the reaction.

(b) A chemical equation needs to be balanced so as to make the number of the atoms of the reactants equal to the number of the atoms of the products.

(c)

1. It does not inform about the physical states of the reactants and the product i.e. whether they are solids, liquids and gases.

2. It does not inform about the concentration of reactants and products.

3. It does not inform about the time taken for the completion of the reaction.

4. It does not inform about the rate at which a reaction proceeds.

5. It does not inform about the heat changes during the reaction i. e. whether the heat is given out or absorbed.

6. It does not inform about the conditions such as temperature, pressure, catalyst etc. which affect the reaction.

7. It does not inform about the nature of the reaction i.e. whether it is reversible or irreversible.

The reaction is 2KI + Cl₂ → 2KCl + I₂

22.4 L at STP 2 × 127 = 254 g

(V₁) volume of Cl₂ gas = 1 L, V₂ = volume of gas at STP =?

(P₁) Pressure = \(\frac{750}{760}\) atm, P₂ = atm

Temperature (T₁) = 10°C + 273 = 283 K,

T₂ = 273 K

\(\therefore\) V₂ = \(\frac{P_1V_1}{T_1}\) x \(\frac{T_2}{P_2}\)

= \(\frac{750\times1\times173}{760\times283\times1}\) = 0.952 L

\(\therefore\) Volume of Cl₂ (g) passed at STP = 0.952 L

Now 22.4 of Cl₂ produces at STP = 254 g of I₂

0.952 L of Cl₂ at STP will produce

= \(\frac{254}{22.4}\) x 0.952 g of l₂

= 10.795 g of l₂.

symbols and formula

Law of conservation of mass

(a) Iron + Chlorine → Iron (III) chloride

4Fe + 3Cl₂ → 2F₂Cl₃

(b) Magnesium + dil sulphuric acid → Magnesium sulphate + water

2Mg + 2H₂SO₄ → 2MgSO₄ + 2H₂

(c) Magnesium + oxygen → Magnesium oxide

2Mg + O₂ → 2MgO

(d) Calcium oxide + water → Calcium hydroxide

CaO + H₂O → Ca(OH)₂

(e) Sodium + chlorine → Sodium chloride

2Na + Cl₂ → 2NaCl

Copper carbonate when heated, it turns Black.

(i) 3Fe + 2O₂ → Fe₃O₄

(ii) 3Fe + 4H₂O → Fe₃O₄ + 4H₂

(iii) N₂ + O₂ → 2NO

(iv) 2Pb₃O₄ → 6PbO + O₂

1. 2K₂O + H₂O → 4KOH   Potassium hydroxide

2. CO₂ + C → 2CO   Carbon monoxide

3. N₂ + 3H₂ → 2NH₃    Ammonia

4. PbCO₃ → PbO + CO₂   Lead(ii)oxide, carbon dioxide

5. 2FeCl₂ + Cl → 2FeCl₃   Ferric chloride

1. 2H₂O₂ → 2H₂O + O₂    water, oxygen

2. H₂ + Cl₂ → 2HCl   Hydrogen chloride

3. 2Na + 2H₂O → NaOH + H₂   Sodium hydroxide,Hydrogen

4. 2CO + O₂ → 2CO₂   carban dioxide

5. Zn + 2HCl → ZnCl₂ + H₂  Zinc chloride, Hydrogen

(a) 1^st and 7^th July 

1. Arthritis: It is an inflammation of joints. It is a painful disorder of bones, ligaments, tendons, etc. In this disorder, joints become swollen, stiff and painful. It can lead to disability. 

2. Arthritis is of three types: 

1. Osteoarthritis: In this disorder, the joint cartilage is degenerated. It is caused by various factors like aging, obesity, muscle weakness, etc. This is the most common type of arthritis that affects hands, knees and spine. 

2. Gouty arthritis (Gout): In this disorder, joint pain occurs due to the deposition of uric acid in joints. If uric acid is produced in excess or is not excreted, it accumulates in joints as sodium urate. The accumulated sodium urate degenerates the cartilage causing inflammation and pain. It generally affects the joints of feet. 

3. Rheumotoid arthritis: It is an autoimmune disorder where body’s immune system attacks its own tissues. In rheumatoid arthritis, synovial membrane swells up and starts secreting extra synovial fluid. This fluid exerts pressure on joint and makes it painful. Membrane may develop abnormal granulation tissue called pannus. Pannus may erode cartilage. Fibrous tissue gets ossified and may lead to stiffness in joints. 

3. Osteoporosis: 

1. In this disorder, bones become porous and hence brittle. It is primarily age related disease and is more common in women than men. 

2. As age advances, bone resorption outpaces bone formation. Hence, the bones lose mass and become brittle. More calcium is lost in urine, sweat, etc., than it is gained through diet. Thus, prevention of disease is better than treatment by consuming adequate amount of calcium and exercise at young age. 

3. Osteoporosis may be caused due to decreasing estrogen secretion after menopause, deficiency of vitamin D, low calcium diet, decreased secretion of sex hormones and thyrocalcitonin.

The ‘dragon kite’ did not possess supernatural power. It was too heavy to fly and to be controlled. So it was a failure.

Mahmood was a kite maker. He was popular throughout the city for good and pretty kite making.

Those were the days of leisure, fun and kite flying, Mahmood was respected. But now in his old age people have no leisure, no fun and no kite flying. Mahmood is also not respected.

Past memories of his life and his little grandson Ali gave him some relief when he was old.

The grown up people had no time for flying kites. They hated it. The children spent money on seeing films. So, many people did not buy the kites.

(d) dreaming

The old man remembered the days of Nawab. The people were very fond of flying kites. Great battles with betting were fought in kite flying.

The writer says that both, men and trees, grow at the same pace if they are not hurt or starved. In their young age both look charming and active. In their old age both stoop a little, grow weak and die.

The writer says that both, men and trees, grow at the same pace if they are not hurt or starved. In their young age both look charming and active. In their old age both stoop a little, grow weak and die.

The writer says that both, men and trees, grow at the same pace if they are not hurt or starved. In their young age both look charming and active. In their old age both stoop a little, grow weak and die.

There were at least two rivals. Each of them tried to tangle his kite with the other. The man who could cut the string of another’s kite was the winner. There was a lot of betting also in it.

(a) gathered

There is a great affinity between trees and men.

Why did the old man continue to make kites even when his shop was no longer there ?

(b) confidence

Correct option (a) health

(c) Mahmood’s house

Reference: These lines have been taken from the lesson ‘The Kite Maker’ written by Ruskin Bond. 

[ N.B. : The above reference will be used for all explanations of this lesson. ] 

Context : In these lines the writer describes the story of a famous kite maker Mahmood. In his young age the business of kite flying flourished but nowadays nobody takes interest in flying the kites. 

Explanation : In these lines Mahmood remembers his old time. So, the writer how much interest and pleasure the people took in flying the kites. He further described that not many people bought kites these days. Adults had disdained them and children spent their money for the pictures. The fields were not more for flying kites. Most of the maidans which had stretched from the old fort walls to the river-bank were covered by the people for their residents and farming.

No longer did people gather under the banyan tree to discuss their problems and their plans.

Context : In this lesson the writer describes the story of a famous kite maker, Mahmood. His young age was full of fun and pleasure. He was the most famous kite maker. So, many people came to him. When he became old, the people had no interest in flying kite. So, he had to pass his old age sitting idle. 

Explanation : In these lines Mahmood remembers the old time. So, the writer describes how much interest and pleasure the people took in flying the kite. Kite flying was the hobby of so many people. They gathered in open spaces and flew kites. There were great battles with high betting. Two rivals flew the kite. Each of them tried to tangle his kite with that of the other and to cut the string of his kite. Thus the winning rival got money.

Context : In this lesson the writer describes the story of a famous kite maker, Mahmood. His kites were very famous and even the Nawab was very fond of flying kites. 

Explanation : In these lines the writer describes a very special kind of kite which Mahmood made on the request of Nawab. It was popular by the name of ‘Dragon Kite’. In it there was a series of small, light paper discs, trailing on a thin bamboo frame. The size of the discs was not equal. The uppermost disc was the biggest and the lowest disc the smallest. Thus, the kite looked like a crawling serpent. It was so heavy and complicated that only Mahmood could fly it. In the sun light it was shining like a dragon and hence it was known as dragon kite.

Context : In his early life Mahmood was known as the best kite maker. He was respected everywhere and by all. But after the death of Nawab no one took interest in kite-flying. People were busy in earning their bread and butter. 

Explanation: In these lines the writer compares the life of Mahmood in his young age and old age. When Mahmood was younger, he had many friends. His well-wishers and neighbours used to come to ask about his health whenever he was sick. But now in his old age no one comes to him. Many of his friends have died. His sons also had grown up and they are also busy in their own occupations. So, Mahmood has no child to play with. Thus, his life has become deserted and he was very sad.

Context: Mahmood, who was a famous kite maker in his young age, has now grown old. He recalls the days of his young age when many people and children came to him to buy his kites. He had so many well-wishers also. But now many of his friends have died and children have no interest in flying kites. So, Mahmood is grieving over his old age. 

Explanation : In these lines the writer makes it clear that there has been a great change in the attitude of people since Mahmood was young. Now, the people are very busy. They have no time to sit under the banyan tree for a long time to gossip and discuss their problems. Mahmood as well as the banyan tree has no importance for the common people. Both are like the things which are fixed permanently at one place and can do no good to others. Only during summer few people sit under the banyan tree to protect themselves from the heat.

Context: In this lesson the writer compares the youth of Mahmood with his old age. In his youth, many children came to Mahmood. Whenever he fell ill, many people came to ask for his health. But now he has grown old and nobody comes to him. 

Explanation: In these lines the writer says why people do not come to him in his old age. The children who bought kites from Mahmood, have now become young. They are now busy earning their livelihood. They are facing struggles in their life. They have no time to come to Mahmood and ask for his well being. They have no attachment, affection or sympathy either with Mahmood or with the banyan tree under which they used to play in their young age.