chemistry: May 2014

Monday, May 12, 2014

EAMCET PREVIOUS PAPER QUESTIONS FORM GASEOUS STATE PART-1

1.The average kinetic energy of one molecule of an ideal gas at 27oC and 1 atm. Pressure is

1) 900 cals K-1 mol-1 2. 6.21×10-21 J K-1 molecule-1
3) 336.7 J.K-1 molecule -1 4. 374.3 J.k-1 mol-1

2.The vapor of a substance effuses through a small hole at the rate of 1.3 times faster than SO2 gas at 1 atm. pressure and 500K The molecule weight of the gas is

1) 49.2 2) 37.9 3) 41.6 4) 83.2

3.40 grams of a sample of carbon on combustion left 10% of it unreached. The volume of oxygen required at STP for this combustion reaction is

1. 22.4l 2. 67.2 l 3. 11.2 l 4. 44.8 l

4.In a flask of ‘V’ litres , 0.2 moles of O2, 0.4 moles of N2, 0.1 moles of NH3 and 0.3 moles of He gases are present at 27oC. If total pressure exerted by these non-reacting gases is 1 atm, the partial pressure exerted by N2 gas is

1. 0.4 atm 2. 0.3 atm 3. 0.2 atm 4. 0.1 atm

5.What is the temperature at which the kinetic energy of 0.3 moles of Helium is equal to the kinetic energy of 0.4 moles of Argon at 400 K ?

1) 400 K 2) 873 K 3) 533 K 4) 300K

6.What is the numerical value of gas constant R in J.mol-1K-1
1)0.0821
2) 83140000
3) 8.314
4) 1.987

7.The compressibility factor for a ideal gas is
1) 1.5
2) 1.0
3) 2.0
4) infinite

8.The kinetic energy of one mole of an ideal monoatomic gas at 270c
1) 900cals
2) 450 cals
3) 500cals
4) 1250 cals

9.The density of neon will be highest at
1) STP
2) 2730c,1 atm
3) oc,2atm
4) 273c,2atm

10.The rate of diffusion of methane at a given temp.is twice that of gas X. The molecular weight of X is
1)64
2)32
3) 4
4) 8

EAMCET PREVIOUS PAPER QUESTIONS FORM ATOMIC STRUCTURE PART-1

1. The wavelength of electron waves in two orbits is 3 : 5. The ratio of kinetic energy of electrons will be:

1. 25 : 9 2. 5 : 3 3. 9 : 25 4. 3 : 5

2. Electrons with a kinetic energy of 6.023×104 J/mol are evolved from a surface of a metal, when is exposed to radiation of wavelength of 600 nm. The minimum amount of energy required to remove an electron from the metal atom is
1. 2.3125×10-19 J 2. 3 × 10-19 J 3. 6.02 ×10-19 J 4. 6.62×10-34 J

3. With increase in Principal Quantum number n, the energy difference between adjacent energy levels in Hydrogen atom

1) Increases 2) Decrease 3) Remains constant 4) Decrease for lower values of n and increases for higher values of n

4 Assertion (A) : The probability of finding an electron in a small volume around a point (x,y,z) at a

distance ‘r’ from the nucleus is proportional to ψ 2 .

Reason (R) :- Subatomic particles have both wave and particle nature

1) Both A and R are true and R is the correct explanation of A

2) Both A and R are true but R is not the correct explanation of A

3) A is true but R is not true 4) A is not true but R is true

5. The velocities of two particles A and B are 0.05 and 0.02 ms-1 respectively. The mass of B is five times the mass of A. The ratio of their de Broglie’s wavelength is

1) 2 : 1 2) 1 : 4 3) 1 : 1 4) 4 : 1

6. Among the first lines of lyman, balmer, paschen and brakett series in hydrogen spectra, which has higher energy?
1) Lyman
2) Balmer
3)Paschen
4) Brackett

7.How many electrons are present in M-shell of the atom of element with atomic number 24
1) 5
2)6
3) 12
4) 13

8. in C-14 isotope the numebr of neutrons would be
1) 6
2) 14
3) 8
4) 10

9. Radius of second Bohr orbit is
1) 2.12nm
2) 0.212nm
3) 0.053 nm
4) 0.0016nm

10. Neutron was discoverd by
1) rutherford
2) thomson
3) goldstein
4) chadwick

FIBRE TO FABRIC

Question: 1. Classify the following fibre as natural or synthetic.

Nylon, Wool, Cotton, Silk, Polyester and Jute

Answer- Nylon and polyester are synthetic fibre

Wool, cotton, silk and jute are natural fibre.

Question: 2. State whether the following statements are true or false.

(a) Yarn is made from fibre. (T)

(b) Spinning is a process of making fibre. (T)

(d) The process of removing seed from cotton is called ginning. (T)

(e) Weaving of yarn makes a piece of fabric. (T)

(f) Silk fiber is obtained from the stem of a plant. (F)

(g) Polyester is a natural fiber. (T)

Question: 3. Fill in the blanks:

(a) Plant fibre are obtained from------ and------

Answer: - plants and animals.

(b) Animals fibre are-------- and -------

Answer: - wool and silk.

Question: 4 - From which parts of the plant cotton and jute are obtained?

Answer- Cotton is obtained from fruits of cotton plant and jute is obtained from stem of the jute plant.

Question: 5 - Name two items that are made from coconut fiber.

Answer: - Rope and doormats.

Question: 6 - Explain the process of making yarn from fiber.

Answer: Fiber is made from yarn by spinning. Spinning is done manually as well as using machines by twisting fiber; like rope making.

Extra Questions: -

Answer the following Questions: -

Questions: 1. Question- Which part of plants give us jute and coir?

Answer: Jute comes from the stem of jute plants, while coir comes from the husk of coconut fruit.

Questions: 2. Question- What is ginning?

Answer- The process of removing cotton seeds from cotton pods is called ginning.

Questions: 3. Question- What is spinning?

Answer- The process of making yarn from fibre is called spinning.

Questions: 4. Mention uses of jute fibre?

Answer- Jute is used mainly for making gunny bags, shopping bags, ropes, carpets, etc.

Questions: 5. Write the name of some manmade fibre?

Answer: Rayon, nylon, polyester, acrylic, etc.

Questions: 6. Write the name of animal fibre?

Answer- Silk and wool.

Questions: 7. What is caterpillar?

Answer: The larva of silk-moth is called caterpillar.

Questions: 8. Why do we need to wear clothes?

Answer- Clothes protect us from heat, cold and rain.

Multiple type questions: -

Questions: 1. Which of the following is obtained from natural sources?

(a) Wool

(b) Nylon

(d) Acrylic

Answer: - (a) Wool

Questions: 2. Which of the following is obtained from animals?

(a) Jute and cotton.

(b) Nylon and polyester

(d) Rayon and acrylic

Answer: - (c) Wool and Silk

Questions: 3. Silk worms are reared on which of these?

(a) On leaves of mulberry plant

(b) On the leaves of banyan plant

(d) On the leaves of cotton plant

Answer: - (a) On leaves of mulberry plant

Questions: 4. Which of the following animals give wool?

(a) Sheep and yak

(b) Elephant and tiger

(d) Snake and duck

Answer: - (a) Sheep and yak

Questions: 5. Which of the following is obtained from hair of an animal?

(a) Silk

(b) Cotton

(d) Wool

Answer: - (d) Wool

Questions: 6. What is the name of process which involves pulling and twisting of strands of a fibre?

(a) Ginning

(b) Weaving

(d) None of these.

Answer: - (c) Spinning

Questions: 7. Which is the right time to cut jute plants?

(a) Flowering stage

(b) Mature stage

(d) Any time after flowering.

Answer: - (a) Flowering stage

Questions: 8. Which part of the jute plant does give fibre?

(a) Root

(b) Stem

(d) Flower

Answer: - (b) Stem

SORTING MATERIALS INTO GROUPS

Question: 1. Name the objects which can be made from iron and wood.

Answer: Wooden items: window, door, sofa, chair, etc.

Iron items: Car, truck, bridge, utensil, grill, etc.

Question: 2. Select those objects from the following which shine.

Glass bowl, plastic toy, steel spoon, cotton shirt.

Answer: Glass bowl and steel spoon

Question: 3. Match the objects given below with the materials from which they could be made. Remember, an object could be made from more than one material and a given material could be used for making many objects.

Question: 4. State whether the statements given below are True or false.

(a) Stone is transparent, while glass is opaque. (F)

(b) A notebook has luster, while eraser does not. (F)

(d) A piece of wood floats on water. (T)

(e) Oil mixes with water. (F)

(f) Sand settles down in the water. (T)

(g) Vinegar dissolves in water. (T)

Question: 5. Given below are names of some objects and materials.

Water, basketball, orange, sugar, globe, apple and earthen pitcher.

Group them as:

(a) Round shaped and other shapes.

Answer: Round-shaped: Basketball, orange, globe and earthen pitcher.

(b) Eatables and non eatables

Answer: Eatables: Water, orange, sugar and apple.

Non-eatables: Basketball, globe and earthen pitcher.

Question: 6. List all items known to you that float on water. Check and see if they will float on an oil or kerosene.

Answer: Items; like wood, cork, Styrofoam, etc. float on water as well as on oil.

Question: 7. Find the odd one out from the following.

(a) Chair, bed, table, baby, cupboard

Answer: Baby is a living being, while others are non-living.

(b) Rose, jasmine, Boat, Marigold, Lotus.

Answer- Boat is a mode of transport, while others are flowers.

Answer: Sand is non-metal, while others are metals.

(d) Sugar, Salt, sand, copper sulphate.

Answer: Sand is insoluble in water, while others are soluble in water.

Extra Questions

Answer the following questions-

Question: 1. Name two materials which are soluble in water.

Answer- Sugar and salt.

Question: 2. Name two transparent and two opaque materials.

Answer- Glass, acrylic sheet are transparent materials, while stone and wood are opaque materials.

Question: 3. What are metals?

Answer- The substance which is hard, has luster and is good conductor of heat and electricity is called metal.

Question: 4. What is transparent material?

Answer: The material which allows light to pass through it is called transparent materials.

Multiple choice questions-

Question: 1. Which of the following is soluble in water?

(a) Sand

(b) Oil

(d) Iron filing

Answer: - (c) Glycerine

Question: 2. Which of the following is insoluble in water?

(a) Chalk

(b) Washing soda

(d) Sugar

Answer: - (a) Chalk

Question: 3. Which of the following is a soft material?

(a) Iron

(b) Glass

(d) Chalk

Answer: - (d) Chalk

Question: 4. Which of the following is a hard material?

(a) Chalk

(b) Wool

(d) Diamond

Answer: - (d) Diamond

Question: 5. Which of the following can float on water?

(a) Iron pin

(b) Wood

(d) Coin

Answer: - (b) Wood

Question: 6. Which of the following materials would sink in water?

(a) Steel spoon

(b) Piece of wood

(d) Toothbrush

Answer: - (a) Steel spoon

SEPERATION OF SUBSTANCES

Question: 1. Why do we need to separate different components of a mixture? Give two examples.

Answer- A mixture may contain one or more unwanted substances which may be harmful.

These impurities are harmful for our health so, we need to separate different components of a mixture. Examples: Pebbles are separated from rice and pulse. Petrol, diesel, kerosene, etc. are obtained from crude oil by a method called distillation.

Question: 2. What is winnowing? Where is it used?

Answer-The process of separation of grains from husk and hay with the help of wind is called winnowing. Farmers use this method for separating the grains from husk and hay.

Question: 3. How will you separate husk or dirt particles from a given sample of pulses before cooking?

Answer: For this, winnowing can be used.

Question: 4. What is sieving? Where is it used?

Answer-The process of separating solid constituents of different particle sizes; through a sieve is called sieving. Sieving is used while separating bran from flour. It is also used while separating pebbles from sand.

Question: 5. How will you separate sand and water from their mixture?

Answer- The mixture of sand and water can be separated by sedimentation and decantation.

Question: 6. Is it possible to separate sugar mixed with wheat flour? If yes, how will do it?

Answer: Yes, it is possible to separate sugar mixed with wheat flour. It can be done by the process of sieving.

Question: 7. How would you obtain clear water from a sample of muddy water?

Answer- We can get clear water from a sample of muddy water by the process of sedimentation, decantation and filtration. Coarser particles of soil would settle down at the bottom and partially clean water can be separated by decantation. The water thus obtained can be further clarified by filtration.

Question: 8. Fill in the blanks.

(a) The method of separating seeds of paddy from its stalks is called---------.

Answer- threshing

(b) When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of -------

Answer- filtration

Answer- evaporation

(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The clear water was then poured off from the top.

The process of separations used in this example is called------------

Answer- sedimentation and decantation

Question: 9 - True or false?

(a) A mixture of milk and water can be separated by filtration. (F)

(b) A mixture of powdered salt and sugar can be separated by the process of winnowing. (F)

(d) Grain and husk can be separated with the process of decantation. (F)

Question: 10 - Lemonade is prepared by mixing lemon juice and sugar in water. You wish to add ice to cool it. Should you add to the lemonade before or after dissolving sugar? In which case would it be possible to dissolve more sugar?

Answer: Ice should be added after dissolving the sugar. Saturation level increases with increase in temperature and vice-versa is also true. So, it is possible to dissolve more sugar in water at room temperature rather than at lesser temperature.

Additional Questions Based on Separation of Substances

Multiple Choice Questions

Question: 1. The process of settling down of particles of insoluble solid in a liquid is called

(a) Decantation

(b) sieving

(d) winnowing

Answer- (c) sedimentation.

Question: 2. A solid substance is dissolved in water. Which of the following methods should be used for separating it?

(a) distillation

(b) evaporation

(d) filtration

Answer- (b) evaporation

Question: 3. Which of the following properties of particles is ideal for winnowing?

(a) Difference in size

(b) difference in colour

(d) difference in shape.

Answer: (c) difference in weight

Question: 4. Which of the following methods is used in separation of chaff from wheat?

(a) handpicking

(b) sieving

(d) sublimation

Answer: (c) Winnowing

Question: 5. Which of the following methods is used in separation of pebbles from rice?

(a) sieving

(b) Winnowing

(d) Handpicking

Answer- (d) Handpicking

CHANGES AROUND US

1.Question.To walk through a waterlogged area,you usually shorten the length of your dress by folding it. can be reversed?

Answer. Yes. This change can be reversed.

2.Question. You accidentally dropped your favorite toy and broke it.Can this change reversed?

Answer.No. This change cannot be reversed.

3.Question. Some changed are listed in the following table.For each change, write in the blank column whether the change can be reversed or not?

Answer. Change------------------------ Can be reversed Yes\ No.

(1) The sawing of a piece of wood--- No

(2) The melting of ice candy-------- Yes

(3) Dissolving sugar in water------- Yes

(4) The cooking of food------------- No

(5) The ripening of a mango---------- No

(6) Souring of milk----------------- No

4.Question. A drawing sheet change when you draw a picture on it. Can you reverse this change?

Answer.If the picture is drawn a pencil, then it can be erased, hence change can be reversed.

But if picture is drawn with c lours, the change cannot be reversed.

5.Question.Give example to explain the difference between change that can or cannot be reversed.

Answer.Some changes can be reversed, like,

(1) Filling water with glass.

(2) Opening\Closing door.

Other change cannot be reversed, like,

(1) Cording of milk.

(2) Ripening of fruit.

6.Question. A thick coating of a paste of plaster of Paris (POP)is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. can the change in POP be reversed?

Answer.No. The change in POP cannot be reversed.

7.Question.A bag of cement lying in the open gets wet to rain during the night. the next day the sun shines brightly. Do you think the changes which have occurred in the cement could be reversed?

Answer. No. the changes which have occurred in the cement cannot be reversed

AIR AROUND US

1.Question. What is the composition of air?

Answer. Air contains some gases in air are mainly nitrogen,oxygen, small amounts of carbon dioxide, and many other gases.Air contains mostly nitrogen and oxygen. These two gases together make up 99% of the air. The remaining 1% is constituted by carbon dioxide and a few other gases, water vapour and dust particles.

2.Question. which gas in the atmosphere is essential for respiration ?

Answer. Oxygen.

3.Question. How will you prove that air support burning?

Answer. Two lighted candles are taken. one candle is covered a fixed in a tumbler containing water. This candle is covered by an inverted glass. After sometime, the covered candle gets extinguished and water rises upto 1/5th is oxygen. The candle extinguished as soon as all the oxygen was used up.

4.Question. How will you so that air is dissolved in water?

Answer.When a tumbler containing water heated, tiny bubles appear on the inner side. These bubles appear before the water starts boiling. So, these must be air bubles. This shows that water contains air.

5.Question. Why does a lump of cotton wool shrink in water?

Answer.a lump of cotton wool shrink in waterbecause the air inside wool cotton is driven out by water. They layer stic together and hence the lump shrinks.

6.Question. The layer of air around the earth is known as:-

Answer.atmosphere.

7.Question. The comppnent of used by green plants to make their food, is :

Answer. Carbon doxide.

8.question. List five activities that are possible due to the presenmce of air.

Answer. (1) Winnowing.

(2) Formation of clouds.

(3) Respiration.

(4) Photosynthesis.

(5) Transpiration.

(6) Flying of birds.

EAMCET PREVIOUS PAPER QUESTIONS FORM ORGANIC CHEMISTRY PART-1

1.The synthesis of crotonaldehyde from acetaldehyde is an example of ....reaction
1) Nucleophilic addition 2) Elimination
3) Electrophilic addition 4) Nucleophilic addition- elimination

2.Which one of the following is not a method for preparing chloroform ?

I) Heating ethyl alcohol with chlorine and alkali
II) Heating acetone with bleaching powder and water
III) Heating chloral hydrate with aqueous sodium hydroxide
IV) Distillation of acetone over iron filings and water
1) II 2) I 3) III 4) IV

3.Which of the following reactions of acetic acid involve C-OH bond?
I) Action of Na II) Formation of acid chloride
III) Action with NaHCO3 IV) Formation of an ester
1) I, II 2) II, III 3) III,IV 4) II,IV

4.The compound that reacts with CH3MgBr to yield methane as one of the products is
1) CH3CHO 2)CH3COCH3 3) CH3COOCH3 4) CH3CH2OH

5. The organic compound which gives peroxy compound on exposure to atmospheric air in the presence of sunlight is
1) C2H5OC2H5 2) CHCl3 3) CH3CH2OH 4) CH3CHO

6. Nitrobenzene undergoes reduction with Zn/alcoholic KOH to form a compound A. The number of Sigma and Pi bonds in A, respectively are (M-2008)

1)17,6 2) 27,6 3) 27,8 4)17,8
7. Which one of the following reactions is called Rosenmued reaction ?

1.Aldehydes are reduced to alcohols
2.Acids are converted to acid chlorides
3.Alcohols are reduced to s hydrocarbons
4.Acid chlorides are reduced to aldchydes

8. Ethyl chloride on reduction with gives compound ‘X’ as important, ‘X” on chlorination with one mole of in the presence of light at ordinary temperature gives ‘Y’ . What is Y ?

1) C2 H6 2) C 2 H4 3) C2 H5Cl 4) C2 H5OH

9. Methyl alcohol when reacted with carbon monoxide using cobalt or Rhodium as catalyst compound ‘A’ is formed, ‘A” on heating with AI in the presence of red phosphorus as catalyst ‘B’ is formed Identify ‘B”
1) CH3COOH 2) CH3CHO 3)CH3CH2I 4) CH3CH3

10.Nitrobenzene on reduction with Zinc and NH4Cl gives
1) Azobenzene 2) Aniline
3) Hydrazobenzene 4) N-Phenyl hydroxylamine

Sunday, May 11, 2014

KEY EAMCET PAPERS

ALKALI METALS

1.b

2.b

3.b

4.b

5.c

6.d

7.d

8.c

9.d

10.a

ALKALINE EARTH METALS KEY

1.b

2.c

3.c

4.b

5.a

6.b

7.c

8.b

9.c

10.d

EAMCET PREVIOUS PAPER QUESTIONS FORM ALKALI METALS PART-1

1. The first ionization energy of lithium is

a) greater than Be

b) less than Be

c) equal to Na

d) equal to F

2.Which pair of elements will have the same chemical properties?

a)13.12

b) 3,11

c) 4,24

d) 2,4

3.Sodium sulphate is soluble in water where as barium sulphate is sparingly soluble because

a) The hydration energy of sodium sulphate is more than its lattice energy

b) lattice energy of barium sulphate is more than the hydration energy

c) the lattice energy has no role to play in solubility

d) The hydration energy of sodium sulphate is less than its lattice energy

4) in case of alkali metals

a) the cation is less stable than the atom

b) the cation is smaller than the atom

c) the cation and the atom have about the same size

d) the cation is larger than the atom

5. On heating sodium metal in a current of dry ammonia gas, the compound formed is

a) sodium nitride

b) sodium hydride

c) sodium amide

d) sodium azide

6.Excess of NaOH with zinc forms

a) Zn(OH)₂

b) ZnO

c) ZnH₂

d) Na₂ZnO₂

7. Which of the following statements is correct?

a) lithium carbonate is soluble in water

b) carborates of Ca,Sr,Ba are soluble in water

c) carborates of Na,K and Co are soluble in water

d) basic carbonate of Mg is soluble in water

8.which is manufactured by the electrolysis of fused NaCl

a) NaOH

b) NaClO

c) NaClO₃

d) Na

9.potassium is kept in

a) water

b) ammonia

c) alcohol

d) kerosene

10. Fire extinguishers contain H₂SO₄ and

a) Na₂ CO₃+ NaHCO₃

b) NaHCO₃ solution

c) Na₂CO₃

d) CaCO₃

Saturday, May 10, 2014

EAMCET QUESTIONS FROM CHAPTER ENVIRONMENTAL CHEMISTRY PART-1

1.The chemical entities present in thermosphere of the atmosphere

1) 2) 3) 4)

2.Which of the following oxides finally dissolve in water to cause acid rain

1) NO, NO₂	2) NO₂, SO₂	3) NO₃, SO₃	4) N₂O₅,SO₃

3.5 l aqueous solution is kept in the presence of oxygen and suitable micro-organism for five days at 20^oC. If the O₂ consumed is 0.2 g, the BOD value of the sample is

1) 4 ppm

2) 0.4 mgl^-1

3) 40 ppm

4) 20 mgl^-1

4.Which of the following is not an air pollutant? 1) CO 2) SO₂3) NO 4) N₂

5.Bhopal gas tragedy of 1984 was caused by

1) Carbon Monoxide 2) Phosgene 3) Methyl cyanate 4) Methyl Isocyanate

6.Which of the following is not an air pollutant?

(1) N₂ (2) N₂O (3) NO (4) CO

7.In which part of atmosphere, ozone layer is present?

(1) Stratosphere (2) Troposphere (3) Mesosphere (4) Thermosphere

EAMCET QUESTIONS FROM CHAPTER NOBLE GASES PART-1

1.The number of pπ −dπ ‘pi’ bonds present in XeO₃ and XeO₄ molecules, respectively

1) 3, 4 2) 4, 2 3) 2, 3 4) 3, 2

2.Which of the following statements is not correct ?

1) In the Dewar’s method for the separation of noble gases, activated coconut charcoal is used.

2) Krypton is used in miners cap lamps.

3) The electron affinity values of noble gases are nearly equal to zero.

4) Xenon gives different colours when mixed with mercury vapour.

3.Which of the following statements about Noble gases are correct ?

(I) XeO₃is an explosive tetrahedral molecule.

(II) In fisher Ringe method, a mixture of CaCl₂and CaC₂ is used to remove N₂and O₂. (III) He and Ne are chemically inert due to lack of d-orbitals and high ionization potential. IV) At 173 K he and Ne are adsorbed on activated charcoal.

The correct answer is

1) I and II 2) II and III 3) II,III and IV 4) I,II, III and IV

4.In the separation of noble gas mixture from air by Ramsay Rayleigh’s first method, the substances used for

the removel of	and O₂ respectively are
1) Cu and Mg	2) Mg and Cu	3) C and CaC₂	4) KOH solution

5.Which one of the following noble gases is used in miner’s cap lamps ?

1) Helium 2) Neon 3) Argon 4) Krypton

6.What is the correct order of occurrence (% by weight) in air of Ne, Ar and Kr ?

	1) Ne > Ar > Kr		2)		3)		4)

7	In Fischer-Ringe's method of separation of noble gases mixture from air, _____ is used.
					σπ 3 2
					CaC90%*NXe*ArFO> CaCOKrNe+10%>KrANeCaCl+
	(1) 90%				sp2 d423	3	2
	(1) 90%				(2) Coconut charcoal
	(3) Sodalime + potash solution				(4)		urea

8.	Which of the following is not correct?
	(1)	has four	and four		bonds.
	(2) The hybridization of			in	is

(3) Among noble gases, the occurance (present by weight) of argon is highest in air.

(4) Liquid helium is used as Cryogenic liquid.

hari

Monday, May 12, 2014

Sunday, May 11, 2014

Saturday, May 10, 2014

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