The results of Class XI is shamefully low since the introduction of CCE in classes up to class X. The CCE ensures pass of every student. It is further emphasized that the student should get admission in the same school. This criteria make the students less responsible and they get good percentage in class X without much knowledge expected of that level.

The students mainly get good grades in formative assessments in which most of the activities are performed in groups. Almost all students of the group are getting almost identical marks and grades. So, even a weak student gets good grades because he is part of the group. These grades scored by him ensures his admission to science group in class XI. Only when the result of Class XI comes he realizes that he is not fit for the science group (or any other group he has chosen).

The teachers of class XI are more worried where the administration wants 100% result out of these students with little aptitude towards the subject. It is high time that the system be reviewed and ensure that only students with aptitude towards science steam come in Science group as well as other streams.

You responses in this regard are welcome. All students and teachers as well as parents are requested to take part in this discussion. Post your views and responses as comments to this post.

Related articles

• Debate on Efficacy of Cce Heating Up (education2home.com)
• CCE is more burden than earlier evaluation system (education2home.com)
• How was CBSE Science Exam for Class X? (physics.2lv.in)
• Class 10 CBSE Science Summative Assessment II (physics.2lv.in)
• CBSE issues guidelines for standard 11 admissions (cbsephysics.2lv.in)
• CBSE working closely with State for CCE (thehindu.com)

CBSE Science exam was today (20 March 2012).

How was the exam?

Many students reported that the exam was quite easy and could easily score 90% and above.

How was the Science exam for you?

Were there any errors in the question paper?

Were there any question out of syllabus?

Were the diagrams and other questions the expected ones?

Were there any questions beyond comprehension?

Respond now….

You can post the difficult and confusing questions as comments to this post and we’ll discuss the solutions

Related articles

• Do students need another exam?(thehindu.com)

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• Ask The CBSE – March 5, 2012 (thehindu.com)
• Combined exam of AIEEE and AIPMT – Top questions to be answered… (edubrite.com)

Click here to Download the Free Issue of Physics World Magazine.

This issue focuses on Physics and Earth

Chemistry

Class – XI

Time – 3 Hrs. Marks – 70

General Instructions :

i) All questions are compulsory.

ii) Q. s 1 to 8 carry 1 makes each. Answer them in one word or in about on sentence.

iii) Q. s 9 to 18 carry 2 marks each. Answer these in about 30 words each.

iv) Q. s 19 to 27 carry 3 marks each. Answer these in about 40 words each.

v) Q. s 28 to 30 are long answer questions carrying 5 marks each.

vi) Use long table if necessary, use of calculator is not permitted.

1. Write IUPAC name of the following compound : 1

2. Write down the formula of the monomer of silicone. 1

3. What would be the effect of increasing pressure on the equilibrium. 1

PCl₅ (g) = Pcl₃ (g) + Cl₂ (g) ?

4. What is the oxidation number of oxygen in Na₂O₂ ? 1

5. What would be the sign of S for the process 2H (g) à H₂ (g) ? 1

6. What is compressibility factor of a gas ? 1

7. Configuration of ion M⁺² is Is² 2s² 2p⁵ what is configuration of atom M? 1

8. How many oxygen atoms would be there in 1 mole of H₂SO₄ ?

9. a) What is the hybridization of each carbon in CH₃ – CH₂ ? 1

b) What is the function of AlCl₃ (anhyd) in Friedel Crafts reaction ? 1

10. How N and S are detected when present in an organic compound together ? (Reaction only) 2

OR

Which is the electrophillic centre in CH₃Br and why ?

11. Why lithium does not form a superoxide but potassium does ? 2

OR

Why BeSO₄ is water soluble but BaSO₄ is not ?

12. Balance the following redox feaction by ion 2

Electron method :

Cr₂ O₇^-2 + Fe⁺² à Fe⁺³ + Cr⁺³ in acidic medium.

13. a) What is the change in internal energy in a process in which 700J of heat is absorbed and 450J of work is done by the system ?

b) Define a spontaneous process in terms of Gibbs energy. 1

14. Show by MO concept which one out of O₂ and O₂+ would be more stable. 2

OR

Explain all the orbital overlaps in a molecule of ethene (C₂H₄) by drawing a sutitable diagram.

15. Calculate the mass of (NH₄)₂ S required to prepare 200 ml of O.1 molar aqueous solution.

(N = 14, H = 1, S = 32)

16. a) Write down the IUPAC name and symbol of the element with at no 119. 1

b) Why Cl has more negative electron gain enthalpy then F in group 17 ? 1

17. Arrange the species : F^-, O^-2, N^-3, Mg ^{+ 2}, Al ^{+ 3} and Na⁺ in the increasing order of ionic radii and give reason. 2

18. Deduce the structural formula of an alkene which on ozonolysls produces propanal and pentanone – 2. 2

19. a) What is Eutrophication ? 1

b) How can photochemical smog be controlled ? 1

c) Give an example of herbicide. 1

20. a) Why atomic radius of Ga is less then the of Al in group 13 ? 1

b) Why white fumes appear around a bottle of anhydrous AlCl₃ ? 1

c) Why Sn⁺² is a reducing agent but Pb⁺² is not ? 1

21. Determine the percentage of Nitrogen in an organic compound, 0.5g of which on kjeldalisation required 10ml of 1M. H₂SO₄ for complete neuteralisation of the ammonia produced. 3

OR

What is the percentage of sulphur in an organic compound 0.15g of which on subjecting to carius method of suphur estimation produced 0.5g of BaSO4

(Ba = 137, S = 32, O = 16) ? 3

22. a) Explain the structure of diborane by drawing a suitable diagram. 2

b) Why SiCl₄ gets hydrolysed but CCl₄ does not ? 1

23. a) Write a reaction by which BeCl₂ can be prepared. 1 b) Why solvay process can not be extended to manfacture K₂CO₃ ? 1

c) Why salts of Be can not be detected by flame test ? 1

24. a) Why hard water does not give lather with soap ? 1

b) Complete the reaction and balance it 1

Pbs + H₂O₂

c) How the presence of H^-ions be confirmed in Ionic hydrides 1

25. For a reaction , H and S are 30.56 KJmol^-1 and 66JK^-1 mol^-1 respectively calculate the temperature above which the reaction

would be spontaneous. 3

26. a) Why does the viscosity of a liquid decreases with increase in temp ? 1

B) What is the pressure exerted by 2 mole of a gas enclosed in a 100ml vessel at 27⁰C ? (Given R = 0.0821 lit atm mol^-1 K^-1) 2

27. a) Why bond angle is NH₃ is lower that in CH₄ even though the same hybridization is involved in both cases ? 2

b) Why H₂O is polar but CO₂ is non polar ? 1

28. a) Mention two limitations of Bohr’s Model of atom 2

b) Calculate the wavelength of an electron moving with a kinetic energy of

3×10^-25J (mass of electran = 9.8 x 10^-31Kg) 3

OR

a) Out at 3d and 4s sub shells which one would have lower

energy and why ? 2

b) What would be the frequency of radiation emitted when an electron moving within a hydrogen atom undergoes transition from fifth to second energy level? 3

29. a) Derive the relationship between k_p and k_c 3

b) The value of k_c for the reaction

2A = B +C is 2 x 10^-3. At a given time the composition of reaction mixture is [A] = [B] = [C] = 3 x 10^-4 M. In which directions will the reaction proceed? 2

OR

a) Derive the relationship between Ka and α of a weak c molor acid HX. 3

b) Calculate the pH of 0.01 M KOH assuming complete dissociation. 2

30. a) Why wurtz reaction is not considered to be a suitable method for preparing

alkanes with odd no. carbon atoms ?

b) Explain the eclipsed and staggered conformation of ethane by Newman’s projection formula. 1

c) Complete the reaction : 1

CH₃ – CH₂ – CH = CH₂ + HBr à

OR

a) Explain the term β – elimination with an example. 2

b) Draw the Geometrical isomers of but – 2 – ene and explain which one would be polar. 2

c) Complete the reaction :

OH

+ Zn

Kerala Government has recently issued directives to prevent free supply of plastic carry bags from shops. Is this a good move?

What’s happening now?

The shopkeepers have started charging for the plastic bags even without asking the customers. This in turn increases the use of plastic rather than decreasing it. Now the customers have adjusted themselves to spend Re. 1/- to Rs. 5/- instead of carrying a carry bag from home.

If the ultimate aim of these drive is to save our mother earth, there must be a ban on plastic and alternative measures must be planned and implemented. Instead of asking the shop keepers to charge for plastic bags, ask them not to keep plastic bags, but sell non-plastic carry bags instead.

It could have been better !

Here are some suggetstions.

• Let the shop keepers supply paper carry bags or non plastic, biodegradable bags.
• If the shopkeepers want to sell carry bags, it must be without the BRAND of their shop/business etc and let them provide good quality reusable bags.