Explore topic-wise InterviewSolutions in .

1. solid 

2. low 

3. C_nH_2n+2 

4. C_nH_2n-2

(i) Add ammonium hydroxide to the solutions of lead nitrate and zinc nitrate dropwise and then in excess.

(ii) Add silver nitrate solution to both sodium chloride and sodium nitrate solution and observe.

(i) Add aqueous hydrochloric acid solution to the solution of lead nitrate and solution of zinc nitrate prepared separately. The solution of lead nitrate would give a white precipitate of PbCl₂ whereas there would be no reaction with zinc nitrate solution.

Pb²⁺ + 2Cl^- ---> PbCl₂(↓) 

(ii) Add aqueous solution of silver nitrate (AgNO₃) to the solution of sodium chloride and solution of sodium nitrate prepared separately. The solution of sodium chloride would give a white precipitate of AgCl whereas there would be no reaction with sodium nitrate solution.

Urine of animals, contains urea which is a compound of ammonia. Urea decompose slowly to produce ammonia. So there is a smell of ammonia near cattle shed. 

 NH₂ - CO - NH₂ + H₂O → 2NH₃ + CO₂

(i)  Add ammoniacal solution of AgNO₃ to both the gases. The one which gives a white precipitate with the solution, is ethyne and the one which does not give any precipitate, is ethane.

(ii)  Methanal gives silver mirror with Tollen’s reagent while ethanol does not give.

The mixture of sodium nitrate and conc. H₂SO₄ should not be heated very strongly above 200°C because

it has following disadvantages. 

(1)  Sodium sulphate is formed at high temperature. Which is hard substance like some and it is very difficult to remove from the distilating flask.

(2)  Glass apparatus may crack above 200°C 

(3)  A part of citric acid vapors decompose to give NO₂ which imparts a yellow color to nitric acid.

(i) Q having pH 5.2 is weak acid

(ii) R having pH 12.2 is strong alkali

Cone. sulphuric acid is a dehydrating agent.

(i) Brass → Copper and Zinc

(ii) Duralumin → Copper, Manganese and Magnesium, Aluminium

CuCO₃+H₂SO₄ → CuSO₄+H₂O+CO₂

ZnSO₄+Na₂CO₃→ Na₂SO₄+ZnCO₃

Period number = 3

Group number = 13/III A

Baeyer’s process

Thirteenth group, third period.

(i) 8NH₃ + 3Cl ⟶ 6NH₄Cl + N₂

(ii)  Fe(OH)₃ + 3HNO₃ ⟶ Fe(NO₃) + 3H₂O

(iiii) ZnO + 2NaOH ⟶ Na₂ZnO₂ + H₂O

1. Above 200 °C the nitric acid decomposes into H₂O, NO₂ and O₂ as it is very unstable to heat. 

2. Sodium sulphate or potassium sulphate will be formed which forms a crust over the mixture thus restricting the release of nitric acid vapours.

Because above 200^oC, nitric acid will decompose.

(i) Bauxite (Al₂O₃.2H₂O)

The most common ore of Al is boxite. Chemical formula is Al₂O_3.

Aluminium has a great affinity towards oxygen and so cannot be reduced by carbon or carbon monoxide. So it is extracted from its oxide by electrolysis.

Metals like copper, lead and iron are placed in the middle of the activity series and re moderately reactive and their oxides can be reduced by carbon, CO and hydrogen.

Mercury and silver are less reactive and are placed lower in the reactivity series. The oxides of these metals are reduced to metals by heating their oxides.

It is an all glass retort.

The above problem is based on A vogadro's law, which states that : 

'Equal volumes of all gases under similar conditions of temperature and pressure contain the same number of molecules'.

The process is called Bayer process.

(i)  Hydrogen gas

(ii)  Nitrogen gas

(iii)  Sulphur dioxide gas

(iii)  Nitrogen dioxide gas

(iv)  Hydrogen sulphide gas

Nitrogen : 82.35 % and hydrogen : 17. 64% 

So N : H is 4.67 : 1, or rounding off

N : H is 5 : 1 

So, the empirical,formula of the gas would be, NH₅.

As the reaction is exothermic, the installation is called HCl over burner is used. The HCl gas is absorbed in water resulting in chemically pure HCl.

(i) Direct absorption of hydrogen chloride gas in water is not feasible as it leads to back suction. 

(ii) “Inverted funnel arrangement” is done to dissolve hydrogen chloride gas in water.

The reaction is highly exothermic.

As the reaction is exothermic, the installation is called HCl over or burner. The HCl gas is absorbed in deionized water resulting in chemically pure HCl.

Laboratory preparation of hydrogen chloride gas can be done by heating NaCl with concentrated sulphuric acid : 

NaCl + H₂SO₄ + 420 K -----> NaHSO₄ + HCl (↑)

Molecular formula = (CH₂Br) x 2 = C₂H₄Br₂

(i) 1 mole of sulphur = 6 x 10²³ atoms = 32 g of sulphur

10²² atoms = (32 x 10²²)/(6 x 10²³) = 32/60 = 0.533 g

(ii) 1 mole of carbon dioxide (CO₂) = 12 + (2 x 16) = 44 g

0.1 mole of carbon dioxide = 0.1 x 44 = 4.4 g

This is because neither zinc atom nor its ion (Zn²⁺) has 1 to 9d-electrons in the (n -1) d-subshell.

This is due to increase in mass and decrease in size.

(i) (c)

(ii) (d)

(iii) (b)

(iv) (a)

(1) Pulverisation 

(2) Calcination

1 gm atom is the mass of 1 mole of monoatomic element

1 mole of Na is equal to 23 gm atom of Na

23 gm of Na = 1 mole of Na

4.6 gm of Na = 4.6 x 1 /23 = 0.2 mole

So, number of gram atoms = 0.2 x 6.022 x 10²³ atoms

= 1.204 x 10²³ atoms

Mahanadi, Godavari and Indrawati. The predominant crop is rice.

It is important to keep in mind the mood of the poet. The poet is in a gloomy, hopeless mood. He is thinking of the death of the nineteenth century and is perhaps worried about the new century that is going to take birth soon. In the nineteenth century all old values and beliefs had come to be disrupted and undermined by the new scientific and technological discoveries. The people were unsure of the next century. They had no hope for something positive in life. When the poet is lost in these thoughts he suddenly hears a shrill happy note of an old thrush. The aged bird whose plumes have been battered by the storm is about to die, yet it chooses to pour out its heart in a forceful manner. It reveals that the music of nature never dies. It is heard in some way in every situation. Though the poet seems to be confused as to why the bird has sounded a discordant note, we feel that there is a veiled hint that there is yet some hope and the new century (20th century) will come with some good to mankind.

‘The Spider and the Fly’ by Mary How itt tells a simple, tragic story in a straightforward manner. The spider and the fly are personified. They act and behave like humans, and are, in fact, metaphors for some kinds of people in real life.

The spider does not give up. He gives the fly a temptation to have a nice feast in his room. Says he :

“I have within my pantry, good store of all that’s nice; I’m sure you ’re very welcome; will you please take a slice? ”

The fly in her wisdom declines the invitation once again emphatically. She says that she knows what he has in his store, and she does not have any desire to see what he has.

The spider, then, resorts to plain flattery. He addresses her as ‘Sweet creature’ and praises her for being witty and wise. He exclaims that her gauzy wings are very pretty and her eyes are very bright. He asks her to come to his drawing-room to have a glimpse of her beauty in a small looking- glass placed on a shelf there. The fly thanks the spider for what he says and then bids him farewell, saying that she will come some other day.

The spider goes into his dark cell, and is confident that the foolish fly will soon return. He weaves a web and sets a table in his room ‘to dine upon’ the fly. Then he comes out and begins to sing praising the beauty of her wings, her colours, her crest on her head, and her eyes. The foolish fly, does come back, enchanted by the flattering words, gets caught and eaten by the spider.

The end of the fly is, no doubt, tragic. But she is herself responsible for her end. She throws all cautions to the wind and is taken in by the cunning spider. Flattery proves to be fatal in her case. She knows well that it is dangerous to enter the spider’s web. Even then she comes very close to the web, so overpowered is she by the flattering words of the spider. The spider cannot be held responsible for what he does. It is the fly who proves to be foolish enough to be tricked by the wily spider. Had she not forgotten what she had heard about the spider’s ‘den’ she would not have met her doom. We all need to learn a lesson from her fate.

Nature, in whatever form it is conceived in ‘The Darkling Thrush’, seems to reflect the mood of the poet. At first, it seems there is a correspondence between the mood of Nature and that of the poet. There is utter gloom in Nature. The light of the sun is fading. Frost appears like a ghost. The clouds in the sky seem to form a canopy. The wind blowing seems to be lamenting over the death of the century.

What the poet hears suddenly and unexpectedly reveals that Nature wants to convey that nothing is permanent. The music of nature never dies. The happy shrill note of the thrush in the utter gloom reminds us that there is no real communication between man and nature. Both are perhaps indifferent to each other. If Nature seems to be gloomy it is only the projection of the gloom within the poet’s mind. The poet has failed to interpret Nature properly.

The crows are omnivores because they are eat both plant products and animals.

Effects of Cytokinin

1. Cell Division. Cytokinins are essential for cytokinesis though chromosome doubling can occur in their absence. In the presence of auxin, cytokinins bring about-division even in permanent cells. Cell division in callus (unorganised, undifferentiated irregular mass of dividing cells in tissue culture) is found to require both the hormones. 

2. Cell Elongation. Like auxin and gibberellins, cytokinins also cause cell elongation. 

3. Morphogenesis. Both auxin and cytokinins are essential for morphogenesis or differentiation of tissues and organs. Buds develop when cytokinins are in excess while roots are formed when their ratios are reversed (Skoog and Miller, 1957). 

4. Differentiation. Cytokinins induce plastid differentiation, lignification and differentiation of interfascicular cambium. 

5. Senescence (Richmond-Lang Effect). Cytokinins delay the senescence of leaves and other organs. 

6. Apical Dominance. Presence of cytokinin in an area causes preferential movement of nu-trients towards it. When applied to lateral buds, they help in their growth despite the pres-ence of apical bud. They thus act antagonistically to auxin which promotes apical dominance. 

7. Seed Dormancy. Like gibberellins, they overcome seed dormancy of various types, including red light requirement of Lettuce and Tobacco seeds. 

8. Resistance. Cytokinins increase resistance to high or low temperature and disease. 

9. Phloem Transport. They help in phloem transport. 

10.Accumulation of Salts. Cytokinins induce accumulation of salts inside the cells. 

11.Flowering. Cytokinins can replace photo periodic requirement of flowering in certain cases. 

12.Sex Expression. Like auxins and ethylene, cytokinins promote femaleness in flowers.

13.Parthenocarpy. Crane (1965) has reported induction of parthenocarpy through cytokinin.

Characteristics of Genetic Code :

1. Triplet Code : Three adjacent nitrogen bases constitute a codon which specifies the placement of one amino acid in a polypeptide. 

2. Start Signal: Polypeptide synthesis is signalled by two initiation codons – methionine AUG or codon and GUG or valine codon. 

3. Stop Signal: Polypeptide chain termination is signalled by three termination codons – UAA (ochre), UAG (amber) and UGA (opal). They do not specify any amino acid and are hence also called nonsense codons. 

4. Universal Code : The genetic code is applicable universally, i.e., a codon specifies the same amino acid from a virus to a tree or human being. Thus, /wRNA from chick oviduct introduced in Escherichia coli produces ovalbumin in the bacterium exactly similar to one formed in chick. 

5. Nonambiguous Codons : One codon specifies only one amino acid and not any other. 

6. Related Codons : Amino acids with similar properties have related codons, e.g., aromatic amino acids tryptophan (UGG), phenylalanine (UUC, UUU), tyrosine (UAC, UAU). (Any four points)

Southern Blot Technique: 

The Southern blot is one way to analyze the genetic patterns which appear in a person DNA. 

Performing a Southering Blot involves :

Source of DNA : White blood corpuscles, blood, semen, saliva, vaginal swabs, skin cells, bone cells, cells from hair root, etc. are used as a source of DNA for fingerprinting. 

The amount of DNA required can be met by 1 micro gram of tissue or 1,00,000 cells.

• Isolation and Extraction – Isolation of DNA from DNA source cells in a high speed refrigerated centrifuge. 

• DNA Amplification – Many copies of extracted DNA are made by PCR technique. 

• Fragmentation/Digestion of DNA by restriction endonuclease to produce VNTRs. 

• Separation of DNA fragments (VNTRs) by size through gel electrophoresis. 

• Single stranded DNA – Denaturing of VNTRs either by heating or chemically treating the fragments in the gel. 

• Southern Blotting – Transferring (blotting) of separated single-stranded DNA fragments to synthetic membranes such as nitrocellulose or nylon. 

• Hybridisation – Using radioactive/labelled VNTR probe. 

• Exposure to X-Ray films/Autoradiography – Detection of hybridised DNA by autoradiography. 

• After hybridisation autoradiography shows many dark bands of different sizes. 

• These bands give a characteristic pattern for an individual DNA.

DNA prints or DNA profiles of dead bodies are compared with DNA prints of the close, blood relatives (sisters, brothers, parents) to determine the identity of the dead bodies.

Particles has wave nature

Reasons for Mendel’s Success : 

• Mendel selected only pure breeding varieties of Pea (Pisum sativum) for his experiments. 

• Mendel took only those traits for his studies which did not show linkage, interaction or incomplete dominance. 

• Mendel took one or two characters at one time for his breeding experiments while his predecessors often studied all the traits simultaneously. 

• Mendel’s experimental plant Pea (Pisum sativum) is ideal for controlled breeding. It is 

• cross-breed manually while normally it undergoes self breeding. 

• He took care to avoid contamination from foreign pollen grains brought by insects. 

• Mendel kept a complete record of every cross, subsequent self breeding and the number of seeds produced. 

• He formulated theoretical explanations for interpreting his results. His explanations were further tested by him as to their validity. 

• Mendel used statistical methods and law of probability analysing his results. 

• Mendel was lucky in selecting those traits, the genes of which were either present on different chromosomes or showed recombination. (Any four points)

de Broglie hypothesis : With every moving particle a wave is associated. This wavelength is given λ = \(\frac{h}{p}\).

p = Momentum of the particle

h = Planck constant.

Causes of infertility : Infertility is the failure to conceive when after to 1-2 years of regular unprotected sex i.e., inability to produce offspring. Infertility can be defined as relative sterility. Infertility is caused by defects found in male, female as well as both.

Infertility in Males:

• Cryptorchidism or failure of testes to descend into scrotum.lt causes azospermia. 

• Absence or blockage of vasa deferentia and vasa efferentia.

• Hyperthermia or higher scrotal temperature due to varicocele (varicose veins), hydrocele or filariasis, tight undergarment, thermal undergarment or working in hot environment, 

• Infection like mumps after puberty, infection of seminal vesicle. 

• Alcoholism inhibits spermatogenesis. 

• Gonadotropin deficiency. 

• Cytotoxic drugs, radiations, antidepressant and anticonvulsant drugs depress spermatogenesis.

Infertility in Females : 

The various causes of infertility in females are as follow :

• Anovulation (nonovulation) and oligoovulation (deficient ovulation). 

• Inadequate growth and functioning of corpus luteum resulting in reduced progesterone secretion and deficient secretory changes in endometrium. 

• The ovum is not liberated but remains trapped inside the follicle. 

• Fallopian tube may fail to pick up ovum, have impaired motility, loss of cilia and blocked lumen. 

• Noncanalisation of uterus. 

• Defective uterine endometrium due to either reduced or excessive secretory activity. 

• Congenital malformation of uterus. 

• Fibroid uterus. 

• Defects in cervix like congenital elongation, occlusion of cervix by a polyp, cervicitis, scanty or excessive cervical mucus. 

• Defective vaginal growth like atresia and transverse septum.

It is the wavelength below which photoelectric effect takes place