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NIOS Silver Jubilee Year


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Dr.Rajeev Prasad

Assistant Director(Academic)& Regional Director(I/C), National Institute of Open Schooling(NIOS),MHRD Govt.of India,Gandhinagar,Gujarat,India

M.Sc.(Chemistry),B.Ed,Ph.D(Organic Chemistry), Post Graduate Diploma in Distance Education(PGDDE) IGNOU,Delhi

Work Experience

1.Ten years of Teaching Experience as PGT(Chemistry),at PVSS DAV Public School,Koderma ,Jharkhand ,India.

2.Worked as an Academic Officer(Chemistry)at NIOS,Ministry of Human Resource Development, Govt.of India,Noida,UP,India, from 24th February 2011 to 26th July 2016
3.Worked as Lecturer(Chemistry) at DAV Institute of Engineering and Technology(DAVIT),Palamaou,Daltonganj,Jharkhand for one year.

4.Worked as Regional Director(I/C)at NIOS Regional Centre,Ranchi,Jharkhand for one year.

5.At present working as an Assistant Director (Academic) & Regional Director(I/C) at NIOS Regional Centre, Gandhinagar, Gujarat,India, from 27th July 2016 till date

My Hobbies

To Play Chess and Badminton

To Listen melodious songs of Lata and Kishore.

Reading Chemistry books,to conduct different activities based on chemical reactions and to develop multimedia programmes for hard concepts in Chemistry.

My Dislikes

I just can't tolerate partiality in any way with anybody by any body

Speaking lies

My favourite colour


Sand Box

Enrollment trends in different subjects at senior secondary level in NIOS

Year Physics Chemistry Biology Mathematics
2012-13 84865 83601 40323 78715
2011-12 84771 83651 42231 80421
2010-11 71781 70364 36135 69512
2009-10 59555 58648 31429 58391
2008-9 55651 55048 27230 52575

Pass Percentage in senior secondary Chemistry at NIOS

Enrollment trends in different subjects at secondary level in NIOS

2012-13 150444 147117
2011-12 149311 142857
2010-11 140662 131943
2009-10 137387 125069
2008-9 119590 109468

Medium Wise Academic Admission 2012-13 in NIOS

Medium Senior Secondary Secondary
Hindi 133499 162767
English 137085 56745
Marathi --- 2447
Telugu --- 1370
Urdu 1041 1437
Gujarati --- 352
Malayalam --- 4565
Oriya --- 9480

Scientific Reasons Behind the Various Traditions and Customs in India

I have tried to popularise the scientific reasons behind some of the traditions, customs we,Indians, follow in our daily life. I thought to start this column, is to understand the basic reason of following some traditions without knowing the reason why we are following them. Normally, we do so by seeing our parents/grand-parents doing it. Whenever we ask them the reason behind these customs, most of the time we get a reply which is related to God or religion or simply saying, “ye hamari parampara hai”.Let us know some of the very interesting scientific reasons behind these customs.

1.Why we worship and offer water to ‘Peepal’ tree ?

Hindu religion asks us to offer water to ‘Peepal’ tree because as per it, it’s the abode of God. The religion asks us not to uproot any ‘Peepal’ tree because it will bring bad omen to us. There is a fear of God created for the ‘Peepal’ tree and we worship it thinking that it is the abode of God and God will get angry if we uproot them.

Our ancestors knew that ‘Peepal’ is one of the very few trees (it can be the only tree) which produces oxygen even at night. You must also know that all trees use carbon dioxide in day time while doing photosynthesis and produce oxygen which is ‘pran vaayu’ for human beings and at night all trees ‘inhale’ oxygen and ‘exhale’ carbon dioxide at night.) But ‘Peepal’ tree ‘exhales’ or produces oxygen even at night. It generates so much oxygen in one minute which is enough for approx 1000 living creatures.

A common man would probably not understand this scientific reason so in order to save this tree because of its unique property they related it to God/religion and a common is, most of the time, God fearing. This fear of God and the belief that a ‘Peepal’ tree is God’s abode we offer water to ‘Peepal’ tree, we do not uproot it and take every care of it.

2.Why we don't add water to Tulsi plant during night time?

The best time of day to water is early morning before the temperatures begin to rise. This gives the plants a good supply of water to face the heat of the day. Early morning also tends to be a time of lower winds and thus reduced evaporation. It is important to water early enough so that the leaves have time to dry before nightfall to avoid development of fungal disease

3.Why Elders advice not to keep the head facing North while sleeping?

We all know that our planet has a magnetic pole stretched from north to south with the positive pole at the north and the negative pole at the south. we too have a similar magnetic stretch with the positive pole at the head and the negative one at the feet.

It is common knowledge that like poles repel and unlike poles attract not only scientific but also in social spheres. When we lay our heads on the north side, the two positive sides repel each other and there is a struggle between the two.

Since the earth has a greater magnetic force, we are always the losers, and rise in the morning with headache or heaviness.

But when we lay our heads in the southern direction, there is mutual attraction and we wake up fit, fresh and free, unless afflicted by some illness.

We also know that our planet revolves itself from west to east, and sun's magnetic field enters earth from east side. This magnetic force enters our head if we lie with head on the east and exits through feet, promoting cool heads and warm feet as per the laws of magnetism and electricity. When the head is laid towards the west, cool feet and hot head -- result -- an unpleasant start for morning.

Now we may realize why the ancient people said, that our intellect improves by east facing head or house, and life lengthens with the head facing south.

4.Why are fishes not able to survive in distilled water?

The skin of the fish is like the skin of the grape fruit. If the fish is in distilled water, there is an osmotic flow of water from outside the fish to the inside because the salinity of the fish body is higher than that of water. Thus there is danger of dilution of the body fluids of the fish or at worst that of being blown out if the fish is to be in distilled water for a very long period of time.

5.Why Diamond is a good thermal conductor and an excellent electrical insulator ?

Diamond crystal is a three-dimensional network of carbon atoms. All carbon atoms in the network are strongly bonded by carbon-carbon covalent bonds.

Therefore diamond crystal has a highly symmetric cubic structure. The carbon atoms in diamond are precisely aligned. Thus diamond is an ideal crystal. Atoms in the crystal lattices in solids vibrate.

These vibrations, called the atomic vibrations facilitate thermal conduction (transport of heat) in solids. In an ideal crystal, the lattices are so precisely aligned that they do not interact with each other.

Therefore an ideal crystal conducts better than a non-ideal crystal resulting in ideal crystals having good thermal conductivity, which is a measure of heat conduction. Diamond being an ideal crystal is thus a good thermal conductor.

Mobile electrons facilitate electrical conduction - flow of current in solids. There are no free mobile electrons in diamond crystal to ficilitate electrial conduction. Thus diamond is an excellent electrical insulator.

6.Why do eggs become hard on boiling?

Egg contain 67 per cent proteins (in egg white) and 33 per cent fats and proteins (in egg yolk). Egg white protein is mostly albumin (ovalbumin and Conalbumin) All proteins have primary,secondary and tertiary structures.

Tertiary structure of egg white protein is due to hydrophobic interactions and hydrogen bonding. They also contain Cysteine amino acid, which has sulfhydryl group (SH).

These sulfhydryl groups form covalent disulfide bonds and hold 2 distant sections of proteins in close proximity. Disruption of the tertiary structure (or 3 dimensional structure) due to heat, chemicals or acidity is called "denaturation".

When we heat an egg, the, heat breaks the intermolecular forces and the tertiary structure gets broken. The proteins unfold from their nature folded structure and precipitate forming a white solid mass.

7.Why we throw Coins into rivers especially when traveling over river bridges?

In the ancient times, most of the currency used was made of copper unlike the stainless steel coins of today. Most of us even know of the ANNAs (made of copper) which were used in the pre-independent times. Copper is a vital metal very useful to the human body. The intake of copper with water is very good for health. Throwing coins in the river was one way our fore-fathers ensured we intake sufficient copper as part of the water. Rivers were the only source of drinking water. Making it a custom by saying it will bring good fortune to us has ensured that all of us follow the good practice.So just think why we are still throwing steel coins in rever? does it contain copper?

8.Why we Join both palms together to greet others”to say namastey?

While greeting others, we join both the hands together. Joining both hands ensures joining the tips of all the fingers together; which are denoted to the pressure points of eyes, ears, and mind. Pressing them together is said to activate the pressure points. This helps us to remember the person for a long time.

9.Why we hang Mango and Neem Leaves to the doors on auspicious days?

On auspicious days and on special occasions, all of us gather at one place along with our relatives and friends. Photosynthesis is a process where in plants take in carbon-di-oxide and give out oxygen. This process helps in circulation of oxygen and in turn keeps the room temperature at an optimum level. Mango leaves and neem leaves are very effective in the photosynthesis process comparative to other plants. Neem leaves purify the bacteria too. In order to keep the temperature cool and to circulate air, we tie mango leaves and neem leaves to all the doors.

10.Why we put rangoli on the floor, with rice powder in the month of December?

In India, the month of December, it is a bit cold month comparative to the whole year. And the small insects and ants that live in the soil would not have food for the winter. Indian tradition of India tells us to help others and not to harm, even knowingly or unknowingly. Inorder to help the small insects, we would put rangoli on the floor, with rice powder. This would help them in providing food for the winter.

Do you know that

  • The average lifespan of a housefly is 20 to 30 days.
  • Dinosaurs did not go extinct due to being generally maladapted or unable to cope with normal climatic change, a view found in many older textbooks. In fact, dinosaurs comprised an extremely adaptive and successful group, whose demise was brought about by an extraordinary event that also extinguished many groups of plants, mammals and marine life.The most commonly cited cause is that of an asteroid impact on the Yucatán Peninsula, triggering the Cretaceous–Paleogene extinction event.Also, not all dinosaurs went extinct.

Chemistry Quiz

Chemistry is an amazing subject which combines a number of different sciences, attempting to make sense of the complicated world we live in. Try our chemistry quiz and see what you really know about topics such as organic chemistry, atoms and Molecules, Chemical reactions, acids, bases and salts. It’s a good practice test for NIOS learners for upcoming exam and increase your knowledge of both chemistry and general science . It is based on revised Science and Technology Course at Secondary level in NIOS.From onward it is for NIOS learners preparing for IITJEE and Medical Entrance examination .

Senior Secondary (Q.NO.41 Onward)

Physical Chemistry

Inorganic Chemistry

Organic Chemistry

Secondary Level Science and Technology(Q.No.1-40)

Answer All questions by clicking on the appropriate option . Finally, click on submit to view your scores.

1. Which one of the following comes under aldehyde?

acetic acid.
ethyl alcohol.

2. The three basic components of an atom are:

protons, neutrons, and ions.
protons, neutrons, and electrons.
protons, neutrinos, and ions.
protium, deuterium, and tritium.

3. The nucleus of an atom consists of:

protons and neutrons
protons, neutrons, and electrons

4. A single proton has what electrical charge?

no charge
positive charge
negative charge
either a positive or negative charge

5. Which two particles would be attracted to each other?

electrons and neutrons
electrons and protons
protons and neutrons
all particles are attracted to each other

6. The atomic number of an atom is:

the number of electrons
the number of neutrons
the number of protons
the number of protons plus the number of neutrons

7. Changing the number of neutrons of an atom changes its:


8. When you change the number of electrons on an atom, you produce a different:

atomic mass

9. The elements of a group in the periodic table-

are isobars
have consecutive atomic numbers
have similar chemical properties
are isotopes

10. Which one among the following nontoxic gases helps in formation of enzymes which ripen fruit?

Carbon dioxide

11. Which one among the following statements is correct?

All bases are alkalis
None of the bases is alkali
There are no more bases except the alkalis
All alkalis are bases but all bases are not alkalis

12. Which was mainly responsible for the Bhopal Mishap in 1984?

Methyl Isocyanate
Carbon dioxide
Carbon mono-oxide

13. Bleaching powder is used in drinking water as a/an


14. Which one of the following is the softest?


15. Which of the following is the Chemical name of the salt we use in our kitchen?

Sodium Chloride
Ammonium Sulphate
Sodium Carbonate
Calcium Chloride

16. Which of the following is not a mixture?

Distilled water

17. Rusting of iron requires -

Oxygen only
Oxygen and Carbon dioxide
Oxygen and water
Carbon dioxide only

18. Which of the following Chemicals is used for fruit ripening?

Calcium carbide
Sodium chloride
Potassium chloride
None of the above

19. Gypsum (CaSO4.2H2O) is added to clinker during cement manufacturing to

a decrease the rate of setting of cement
bind the particles of calcium silicate
facilitate the formation of colloidal gel
impart strength to cement

20. Which one among the following is a strong smelling agent added to LPG cylinder to help in the detection of gas leakage?


21. Which one among the following substances evolves heat when dissolved in water?

Calcium oxide
Potassium nitrate
Sodium chloride

22. Dead organs are generally stored in formalin. Formalin is

aqueous formaldehyde
aqueous ferrous sulphate
aqueous formic acid
aqueous ferric alum

23. A student heated some sulphur in a spatula and collected the gas 'X'. Which one among the following is correct about 'X'?

X is SO2 and it turns moist litmus to blue
X is SO3 and it turns moist litmus to red
X is SO2 and it turns moist litmus to red
X is SO3 and it turns dry litmus to blue

24. When concentrated H2SO4 spills on the surface, it should be immediately cleaned:

with a piece of cloth
by adding cold water
by adding solid Na2CO3
by adding solid BaCl2

25. A solution of zinc chloride cannot be stored in a vessel made of


26. Concentrated, HNO3 can be stored in container made up of—


27. The metal, which is a constituent of Vitamin B12, is


28. Chemical name of bleaching powder is:

Calcium Chlorate
Calcium Chloro hypochlorite
Calcium oxy chloride
Calcium bi Chloride

29. Why is phosphorus kept under water ?

to make it durable
to make it wet
to save it from catching fire when exposed to dry air
water forms a protective coating on it

30. Which of the following is not a compound of calcium?


31. Which of the following is not a chemical reaction?

burning of coal
conversation of water into steam
digestion of food
burning of paper

32. Which of the following has the same atomic number and atomic weight?


33. Which of the following has a pH less than 7?

pure water

34. The names of the scientists, Newlands, Mandeleev and Meyer are associated with the development of

atomic structure
periodic table of elements
discovery of elements

35. The most malleable metal is


36. The members of a homologous series have

the same physical properties
different functional groups
same chemical properties
different methods of preparation

37. The melting and boiling points of ionic solids are

very low
of intermediate range

38. The gas used in the manufacture of vanaspati from vegetable oil is

Carbon dioxide

39. Saturated hydrocarbons have

Single Bonds
Double Bonds
Triple Bonds
Two Double Bonds

40. Isotopes of an element

are physically identical with each other
are chemically identically with each other
are not identical with each other
have the same mass numbers

41. The spin only magnetic moment of Hg[Co(SCN)4] in bohr magneton units is


42. 3 moles of an ideal gas undergoes reversible isothermal expansion from 3 L to 5 L at 400 K. What is the enthalpy change involved in the process?

20 KJ
80 KJ
0 KJ
800 KJ

43. Given: Ag + + NH3 ⇌ [Ag(NH3)] +, K1 = 2 x 10 3 ; [Ag(NH3)] + + NH3 ⇌ [Ag(NH3)2] +, K2 = 4 x 10 3 . The instability constant of [Ag(NH3)2] + is then equal to

8 x 10 6
6 x 10 −3
8 x 10 −6
0.125 x 10 −6

44. The reaction A ¾® B follows first order kinetics. Concentration of A drops to 0.025 M from 0.1 M in 60 minute. Find the rate of the reaction when the concentration is 0.01 M.

3.33 × 10 −4 mol.minute −1
2.31 × 10 −4 mol.minute −1
1.82 × 10 −2 mol.minute −1
1.55 × 10 −4 mol.minute −1

45. Which of the following would convert 2-hexyne into cis-2-hexene?

H2 / Pd-BaSO4 poisoned with CaCO3
Li / NH3
H2 / Pt

46. Which are the respective methods chiefly employed for the extraction of lead and tin from their ores?

Cyanide reduction and carbon reduction
Carbon reduction and electrolytic reduction
Self reduction and carbon reduction
Self reduction and electrolytic reduction

47. Which of the following is an important reactive electrophile in aromatic ring nitration?


48. Which of the following is phenol?


49. What is the order of reactivity of the following compounds in electrophilic substitution I toluene II nitrobenzene III benzene IV phenol ?(more reactive > less reactive)

I > II > III > IV
IV > III > II > I
I > III > IV > II
IV > I > III > II

50. What is the order of reactivity of the following compounds in electrophilic substitution I chlorobenzene II aniline III ethylbenzene IV benzoic acid? (more reactive > less reactive)

I > II > III > IV
II > III > I > IV
I > III > IV > II
II > I > IV > III

51. The first ionization potential of Na is 5.1 eV. The value of electron gain enthalpy of Na+ will be

– 5.1 eV
–10.2 eV
+ 2.55 eV
– 2.55 eV

52. An unknown alcohol is treated with the “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism:

tertiary alcohol by SN1
secondary alcohol by SN2
tertiary alcohol by SN2
secondary alcohol by SN1

53. The molarity of a solution obtained by mixing 750 mL of 0.5 (M) HCl with 250 mL of 2(M)HCl will be

1.00 M
1. 75 M
0.975 M
0.875 M

54. Which of the following is the wrong statement?

O3 molecule is bent
Ozone is violet-black in solid state
Ozone is diamagnetic gas
ONCl and ONO– are not isoelectronic
All options are correct statements

55. A solution of (–) –1 – chloro –1 – phenylethane is toluene racemises slowly in the presence of a small amount of SbCl5, due to the formation of

free radical

56. A compound with molecular mass 180 is acylated with CH3COCl to get a compound with molecular mass 390. The number of amino groups present per molecule of the former compound is:


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