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CHEMISTRY

CLASS-XI

Time Allowed: 3 hours Maximum Marks: 70

General Instructions:

I) All questions are compulsory.

ii) Question number 1 to 8 are short answer questions and carry 1mark each.

iii) Question number 9 to 18 are short answer questions and carry 2 marks each.

iv) Question number 19 to 27 are also short answer questions and carry 3 marks each.

v) Question number 28 to 30 are long answer questions and carry 5 marks each.

vi) Use log tables if necessary

1. Write the electronic configuration of Fe³⁺ ion (Atomic number of Iron = 26).

2. Why does boron form electron deficient compounds?

3. Tertiary carbocation is more stable than Secondary. Explain why?

4. How does molarity change with temperature?

5. Write the IUPAC name of tertiary butyl alcohol.

6. An atomic orbital has l=2.What are the possible values of m?

7. Find out the oxidation number of manganese in MnO₄^- and MnO₄^2-.

8. Carbon shows the property of catenation remarkably. Assign a reason for this statement.

9. Write any two points of differences between sigma and pi bond.

OR

a) How many sigma and pi bond are present in the molecule:

CH₂=CH-CH=CH₂.

b) Which type of hybrid orbital is used by the second carbon atom in the following molecule.

CH≡C-CH₂-CH=CH₂

10. What is the density of SO₂ gas at 27^oC. (Atomic Weights: S=32, O=16, R=0.0821l/K/mol.

11. What happens when

a) Lead sulphide is reacted with hydrogen peroxide solution.

b) Chlorine reacts with milk of lime. Write chemical equations for reactions involved.

12. Why do real gases deviate from the ideal behaviour? What are the conditions under which real gases show ideal behaviour?

13. The mass of an electron is 9.1×10^-31 Kg. If its kinetic energy is 3×10^-25 J, calculate its wavelength.

14. Account for the following

a. The first ionization enthalpy of Mg is greater than that of Al.

b. Oxygen has a lower electron gain enthalpy than sulphur.

15. Calculate the bond order of O₂⁺ and O₂^2- molecular ions and predict their magnetic behaviour.

16. Explain the following:

a. Wurtz reaction

b. Huckles Rule

17. Account for the following :

a. Pentane has higher melting point than 2-methyl butane.

b. Ethyne is more acidic than ethane.

18. What are electrophiles and neucleophiles? Give one example of each.

19. Write the net ionic equation for the reaction of potassium dichromate(VI) with sodium sulphite in an acid solution to give chromium(III) ion and the sulphate ion.

OR

Permanganate (VII) ion in basic solution oxidises iodide ion to produce iodine and manganese dioxide. Write a balanced ionic equation to represent this redox reaction.

20. Write short notes on :

a. Photochemical Smog

b. Ozone Hole

c. Acid Rain

21. a. How will you prepare hydrogen peroxide by industrial method.

b. What happens when

i. ionic hydrides are treated with water?

ii. Boron tri-fluoride reacts with sodium hydride?

22. a. Define the term conjugate acid-base pair.

b. The value of Kc for the reaction 2A↔B+C is 2×10 ^-3 at 500K at a given time. The composition if reaction mixture is [A]=[B]=[C]= 3×10^-4 M. Is the reaction mixture at equilibrium? If not, what is the direction of net reaction?

23. State Le-Chatelier’s Principle. What are its applications in the manufacture of Ammonia in Habers Process?

24. How will you detect the presence of nitrogen in Lassaigne’s Test .

During estimation of nitrogen by kjeldahl’s method the ammonia evolved from 0.5g of the compound neutralised 10ml of 1M H₂SO₄.Find out the percentage of nitrogen in the compound.

25. Draw the structure of:

a. Di-borane

b.AlCl₃

C.BeCl₂ in solid state

26. a. What do you understand by common ion effect?

b. Determine the solubility of barium sulphate in 0.05M in barium chloride solution.(Ksp-BaSO4=1.1×10^-10).

27. Why lithium shows anomalous behaviour in the group. Give two points of similarities between lithium and magnesium.

28. Explain the following with suitable examples:

a. Inductive Effect.

b. Resonance Effect.

c. Hyper-conjugation.

OR

Define Isomerism. Explain the type of isomerism shown by

a. But-2-ene.

b. Conformations of Ethane.

29. a. SiF6 ^2- is known where as SiCl6 ^2- is not. Give possible reason.

b. Why is boric acid considered as a weak acid?

c. What are silicones?

d. CCl₄ does not hydrolyse unlike SiCl₄.

e. Tl(1) compounds are more stable than Al(1) compounds. Give reasons.

OR

a. Why does BCl₃ act as a Lewis acid?

b. What is dry-ice? Why is it so called?

c. What is water gas? How is it prepared?

d. Which is the basic building unit of all silicates?

e. What are zeolites?

30. How will you bring about the following conversions?

i. Propene to 1- bromo-propane.

ii. Benzene to acetophenone.

iii.Ethyne to acetaldenhyde.

iv.Ethene to formaldehyde.

v.Sodium Benzoate to Benzene.

OR

What happens when

a. Ethyne gas is allowed to pass over red hot iron tube.

b. Calcium carbide is treated with water.

c. Propene is treated with dilute KMnO4.

d. Benzene is treated with chlorine in presence of UV light.

e. Phenol is treated with heated zinc dust.

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1

Blood cells collapse when suspended in saline water. Account for it.

(1)

2

Name any two neutral oxides.

(1)

3

a) What is the principle behind reverse osmosis?

b) Which substance is usually added into water in the car radiator to act as antifreeze?

(2)

4

State Raoult’s law for a solution containing non-volatile solute.

(2)

5

Complete the following equations and also balance them.

i) NH₄Cl + Ca(OH)₂

ii) Zn + HNO₃

iii) P₄ + SOCl₂

iv) MnO₄ + HCl

(2)

6

Draw the structures of the following compounds.

i) Peroxodisulphuric acid

ii) Phosphorous acid and account for the basicity of phosphorous acid.

(2)

7

45 g of ethylene glycol ( C₂H₆O₂) is mixed with 600g of water. Calculate (a) the freezing point depression and (b) the freezing point of the solution.

(3)

8

2 g of benzoic acid (C₆H₅COOH) dissolved in 25 g of benzene shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9 K Kgmol^-1. What is the percentage association of acid if it forms dimer in solution?

(3)

9

Arrange the following in the order indicated.

i) MF, MCl, MBr, MI – Decreasing ionic character.

ii)HOCl, HOBr, HOI – increasing acidic strength

iii)NH₃, AsH₃, SbH₃, PH₃ – Decreasing bond dissociation enthalpy

(3)

10

Give reasons for the following observations.

i)Halogens are strong oxidizing agents

ii)Noble gases have large positive electron gain enthalpy.

iii)Sulphur shows paramagnetic character in vapour phase.

(3)

11

How do you prepare XeO₃ from XeF₄? Write equation. Draw the structure of XeF₆. Mention any two applications of He gas.

(3)

12

i) How is O₃ estimated quantitatively?

ii)H₂SO₄ is a moderately strong acid. Give evidence.

ii)Though N₂ exhibits +5 oxidation state, it doesnot form pentahalide. Why?

iv)Mention the conditions required for the maximum yield of NH₃.

v)What happens when Cl₂ reacts with excess NH₃ and NH₃ reacts with excess Cl₂. Give equations.

(5)

13

i) With the help of a graph explain positive deviation.

ii)The vapour pressure of pure liquids A & B are 450 & 700mm Hg respectively at 350K. Find out the composition of the liquid mixture if total vapour pressure is 600mm Hg. Also find the composition of the vapour phase.

(5)

1

Express the following in the scientific notation:

a) 0.000456 b) 500.0

(1)

2

Name the experiment which is used to find the charge of an electron & what is the charge of an electron?

(1)

3

What are the drawbacks of Rutherford’s atomic model?

(1)

4

Round up the following up to three significant figures.

a) 46.216 b) 10.4107 c) 0.04597 d) 2808

(2)

5

Calculate the number of atoms in the following;

a) 52 moles of Ar b) 52g of He.

(2)

6

What is the SI unit of mass? How is it defined?

(2)

7

State law of multiple proportion with an example.

(2)

8

The density of 3M solution of NaCl is 1.25g/ml. Calculate molality of the solution.

(2)

9

Define isobars with examples.

(2)

10

Mention the two developments which played a major role in the formulation of Bohr’s model of an atom.

(2)

11

The atomic number and mass number of Calcium are 20 & 40 respectively. Find out the number of electrons, protons and neutrons in a Ca²⁺ ion.

(2)

12

a) How many seconds are there in 3 days?

b) A jug contains 5L of milk. Calculate the volume of milk in m³.

(3)

13

Calculate the concentration of HNO₃ in moles per litre in a sample which has density 1.41g/ mL & the mass percent of nitric acid in it being 69%.

(3)

14

A compound contains 4.07% Hydrogen, 24.27 carbon and 71. 65% chlorine. Its molar mass is 98.96g. What is the empirical formula of the compound?

(3)

15

Write notes on Thomson’s plum pudding model of atom with its important features.

(3)

16

What are the conclusions drawn by Rutherford in his gold foil experiment?

(3)

17

i) Define limiting reagent.

ii) 50.0kg of N₂ (g) and 10.0kg of H₂ (g) are mixed to produce NH₃ (g). Calculate the NH₃(g)

produced. Identify the limiting reagent in this reaction.

(1+4)

2. Nitrogen is inert compared to phosphorous why? (1)

3. Give an example of shape selective catalyst? (1)

4. What are aerosols give example. (1)

5. Why do Zr and Hf exhibit similar properties ? (1)

6. Assign a reason (2)

a)Ammonia is stronger base than phosphine

b)Catenation tendency of Sulphur is more than Oxygen .

7. Complete the eqn (2)

(i)Ca₃P₂ + H₂O → (i) Cu²⁺ + NH₃ →

8.Explain the role of (2)

a)Cryolite in the electrolytic reduction of alumina b)CO in the purification of Ni

9.What is the role of stabiliser and depressant in forth floatation process? (2)

10.What is te difference between multimolecular and macromolecular colloid ? Give example of each. (2)

11. Explain what is observed when (3)

a.KCl , an electrolyte is added to hydrated ferric oxide sol b.an electric current is passed through a colloidal solution c.a beam of light is passed through a colloidal solution

12.Describe how the following changes are brought about. (3)

a.Pig iron into Steel. b.Zinc Oxide into matalic zinc. c.Impure titanium into pure titanium.

OR

Describe the role of

a.NaCN in the extraction of gold from gold ore . b.SiO₂ in the extraction of Cu from copper matte.

c.Iodine in the refining of zirconium..

13.Draw the structure of the following. (3)

a.H₂S₂O₇ . b.H₂SO₄. c.H₃PO₄

14. Explain the following by giving reason

a.Out of C and CO which is a better reducing agent for ZnO (3)

b.Reduction of metallic oxide easier if the metal formed in liquid state at the temperature of

reduction.

c.Cr₂O₃+2Al Al₂O₃ + 2Cr ∆G(-) =-421 KJ is thermodynamically feasible as it is apparent from

the Gibbs energy value. Why does it not take place at room temperature?

15. What is adsorption isotherm ?Explain freundlich adsorption isotherm with the help of graph (3)

16. a. Out of the ions Cu²⁺ ,Co²⁺,Tc⁴⁺ which one will be

colourless in aqueous solution and why^? (5)

[At. Number of Cu=29,CO=27,Ti =22]

b.If each one of these species is in turn placed in a magnetic field how will it respond and why?

c. Why is Mn²⁺ more stable than Mn³⁺

d.Transition metals have high melting and boiling points?

e. Transition elements have great tendency for complex formation

OR

a.There is a gradual decrese in the atom size of transition elements in a series with

increasing atomic numbers

b.Lanthum and lutetium donot show colouration in solutions

(At no La =57 ,Lu= 71)

c.The enthalpies of atomisation of transition metals are quite high

d.Among the di valent cations in the first series of transition elements manganese exibit

maximum paramagnatisam.

e. Cu⁺ ion is not known in aqueous solution.

Duration: 3 hrs Maximum marks: 70

General Instructions:

All questions are compulsory.

i)Marks for each question are indicated against it.

ii)Question numbers 1 to 8 are very short answer questions and carry 1 mark each.

iii)Question numbers 9 to 18 are short answer questions and carry 2 marks each.

iv)Question numbers 1 9 to 27 are also short answer questions and carry 3 marks each.

v)Question numbers 28 to 30 are long answer questions and carry 5 marks each.

vi)Use logarithm tables if necessary. Use of calculator is not allowed.

Questions:-

INSTRUCTIONS:

* Answer all the questions:

* Questions 1 to 8 carry one mark each. Answer them in one word or a sentence.

* Questions 9 to 18 carry 2 marks each. Answer them in 20 to 30 words.

* Questions 19 to 27 carry 3 marks each. Answer them in 40 to 50 words.

* Questions 28 to 30 carry 5 marks each. Answer them in 70 words.

* There is no overall choice. However there is internal choice in one question each

of two mark and three marks questions. All 5 marks questions have internal

choice.

* Calculator or any other electronic items are not allowed. However logarithm

book may be used for calculations.

1. Blood cells collapse when suspended in saline water. Give reason. (1)

2. Why is shape selective catalyst highly specific? (1)

3. What is the difference between pig iron and cast iron in terms of amount of

carbon present? (1)

4. Write one example each for homoleptic and heteroleptic complexes. (1/2 +1/2)

5. Write the IUPAC name of (1)

CH₃ OC₂H₅

6. When benzoic acid is treated with CH₃Cl and anhydrous AlCl₃ ring substitution

doesn’t take place. Why? (1)

7. How do you convert ethanamide to methanamine? Write balanced equation

only. (1)

8. Name the linkage connecting the nucleotide units in DNA. (1)

9. Define the terms a) Unit cell b) Co-ordination number of a particle in close

Packing. (2)

(OR)

Write an example of intrinsic semi conductor? How can you increase their

conductivity?

10. If sodium is present in a simple cubic lattice and the radius of one atom is

100pm, calculate the packing efficiency of the crystal. (2)

11. Calculate the mass of Ascorbic acid (C₆H₈O₆) to be dissolved in 75g of acetic

acid to lower its melting point by 1.5°C.k_f = 3.9 K Kg Mol^-1. (2)

12. State Raoult’s law for the solution containing non-volatile solute. What type of

deviation is shown by Ethyl alcohol and water solution. (1+1)

13. Differentiate between order of a reaction and molecularity of a reaction (2)

14. Give reason why? (1+1)

a) C is a better reducing agent for ZnO than CO above 805°C.

b) NaCN is used in froth floatation method of purification of PbS.

15. Draw the structure of (2)

a) S₆ molecule b) HClO₄ molecule

16. Write the IUPAC name of [Co(NH₃)₅(NO₂)]Cl₂. This compound can be prepared

in two different colored crystalline forms. What could be the structural

difference in the two forms? (1+1).

17. Complete the following reactions. (1+1)

a) 2 Cl + 2 Na Ether

b) C₆H₅ CH₂ CH = CH₂ + HBr

18. Write the S_N1 Mechanism involved in the conversion of (CH₃)₃C-Br to

(CH₃)₃C- OH (2)

19. a) Draw the structure of activated complex formed when H₂ & I₂ react to form

HI. (1)

b) A wood piece found in a excavation site contain 75% of C¹⁴ content as the

fresh wood contain. If the half life period of C¹⁴ = 5730 years, find the age of

the wood. (2)

(OR)

a) In a reaction, 5g of a reactant reduced to 2.5g in 10 hr. When 10g of the (1)

reactant is taken, it took 20 hr to reduce to 5g. What is the order of the reaction?

b) For a first order reaction, the rate constant at 400K is 2.25×10^-6 s^-1. Calculate the rate constant at 500K if the activation energy for the reaction is 250KJ/mol.

20. a) Define the terms – (2)

i) Dialysis ii) peptisation

b) Which among the following is most suitable for coagulation of

Fe₂O₃.xH₂O/Fe³⁺ colloid? Why? Al³⁺, PO₄^3- , Na⁺, Br^-. (1/2 +1/2)

21. a) Arrange the following in the decreasing order of the property mentioned.

H₂Se, H₂S, H₂Te, H₂O (Bond angle)

HClO₂,HClO₄, HClO, HClO₃ (acidic character) (2)

b) H₃PO₂ (metaphosphoric acid) is a strong reducing agent. Write an equation to prove this property. (1)

22. i) Though F₂ has less tendency to gain electron than Cl₂ (Δ_egH for Cl₂ is more –ve

than that of F₂), it is a strong oxidizing agent than Cl₂. Why? (1)

ii) Why is He used in diving apparatus? (1)

iii) Why does NO₂ dimerise? (1)

23. A colorless crystalline organic solid (A), having carbolic smell is acidic in

nature. ‘A’ when treated with Bromine water gives white precipitate (B). ‘A’

when treated with NaOH and CO₂ followed by hydrolysis gives compound

(C).C can be used for the preparation of Aspirin. Identify A, B, C and write

equations for all changes. (3)

24. a)Gabriel phthalimide synthesis is not suitable for the preparation of Aniline.

Why? Write equation for the preparation of ethanamine by this method. (2)

b) Why is it necessary to acetylate aniline before nitration? (1)

25. a) Name the disease caused by the deficiency of vitamin E. (1)

b) Among 1°,2°,3°& 4° structures which structure decides whether the protein is

globular (or) fibrous? Which type of forces stabilize the 2° structure of protein?

c)How do you prove that glucose contain one primary alcohol group? (1+1)

26.a) Is PVC a thermo plastic (or) thermosetting plastic? Why is it called so? (1)

b) state whether the following polymer is condensation polymer or addition

polymer ? Write the structure and name of monomers involved in this polymer.

( NH CO NH CH2 )_n (2)

27.a) What do you mean by Agonist and Allosteric inhibitors? (2)

b) Soaps do not work in hard water. Why? (1)

28. a) Write two advantages of fuel cell over other cells. (2)

b) Two electrolytic cells containing AgNO₃ & CuSO₄ solutions as electrolytes

are connected in series. If two amperes of current is passed through the solutions

for 8 min, What is the mass of silver & copper deposited? (Atomic weight of

Cu=63.5u & Ag=108u) (2)

c) When Iron electrode at standard conditions is connected to standard hydrogen electrode to measure its standard potential, Which electrode act as anode? Why?

(OR)

a) Calculate the cell potential (E_cell) of the voltaic cell which is represented as

Cr(s) / Cr³⁺(0.001M) // Cd²⁺ (0.01M) / Cd (s) (3)

Given that E°_{Cr3+ / Cr} = – 0.74v & E°_{Cd2+ / Cd} = – 0.40.

b) State Kohlrausch law of independent migration of ion and one of its use? (2)

29.a) What do you observe when K₂MnO₄ solution is acidified? support your

observation with equation. (2)

b) Answer the following related to d- Block elements-

i) For ‘Fe’ the third ionization potential is less than expected.

ii) Both Cr²⁺ and Mn³⁺ have d4 configuration but Cr²⁺ is reducing and Mn³⁺

is oxidizing. Why?

iii) d- Bolck elements & their compounds can act as catalyst. (3)

(OR)

a) What is lanthanoid contraction? Write its consequences? (2)

b) Actinoids show greater number of oxidation state than Lanthanoid. Why?(1)

c) D- block elements form complexes easily. Why? (1)

d) The enthalpy of atomization is high for d-block element than s-block elements. Why? (1)

30.a) Write one example each for i) Wolff-Kishner reduction. (2)

ii) Hell-Volhard Zelinsky reaction.

b) The pKa value for benzoic acid,4-nitrobenzoic acid, 4-methoxy benzoic acid

are 4.19,3.41,4.46 respectively. What do you suggest about the effect of

substituents on the acidic character of these compounds. (2)

e) Among Acetaldehyde and acetone which is more reactive towards nucleophilic addition reaction? Why? (1)

(OR)

a) Distinguish between the compound s using chemical test and write equation.

i)Benzoic acid & ethyl benzoate.

ii)Ethanal & propanal.

b) Write the equation for cross aldol condensation reaction between Benzaldehyde and acetaldehyde. (2)

c) Aldehydes & ketones have less boiling point than alcohols.Why? (1)

******************************************************************

Instructions

· Answer all questions.

· Questions 1 to 8 carry one mark each. Answer them in one word or sentence.

· Questions 9 to 18 are short answer questions and carry two marks each.

· Questions 19 to 27 are also short answer questions and carry three marks each.

· Questions 28 to 30 are long answer questions and carry 5 marks each.

1. What are the physical state of dispersed phase and dispersion medium of emulsion?

2. The formula of a compound is A₂B₃ with a hcp lattice. What fraction of tetrahedral voids are occupied?

3. What is the purpose of adding xanthates to sulphide ores?

4. What is the charge on the sol formed when KI is added to excess AgNO₃?

5.

Pentavalent Bismuth is a strong oxidizing agent. Why?

6. Write IUPAC name of

7. What is carbylamine reaction?

8. Both cellulose and starch are made up of glucose units. Starch can be digested by humans but cellulose cannot be digested. Why?

9. (i) What is the reason for abnormal molecular mass of solute?

(ii) A person suffering from high blood pressure should take less common salt. Why?

10. Give reason

a) 1 gm. of pulverized wood burns faster than 1 gm. of a piece of wood.

b) Reactions of higher molecularity are rare.

11. How will you distinguish between o/w and w/o emulsions?

12. The free energies of formation of FeO(s) and CO(g)are given at 673K and 1073K.

G_FeO⁰= -375 kJ/mol , G_CO= -325 kJ/mol at 673K

G ⁰_FeO= -275 kJ/mol , G ⁰_CO = -450 kJ/mol at 1073K

On the basis of the above data, predict the temperature at which carbon can be used as a reducing agent for FeO.

13. Give reasons-

(i) SF ₆ does not undergo hydrolysis

(ii) NO becomes brown when released in air.

14. In the titration of Fe ²⁺ ions with KMnO₄ in acidic medium why dilute H₂SO₄ is used and not dil. HCl. Give necessary equations.

OR

An orange coloured solution A changes to an yellow coloured solution B on increasing the pH and the reverse happens on decreasing the pH.Identify A and B and give equations.

15. Which one undergoes SN¹ reaction faster?

1)C₆H₅CH₂Br or (C₆H₅ )₂ CHBr

2) CH₂ =CH-CH₂Cl or CH₂=CH-CH₂I

16. (i)Why chloroform has to be stored in dark coloured bottles?

(ii) Why aryl halides do not undergo nucleophilic substitution reactions easily?

17. Complete and name the reactions

1. C₆H₅OH ?

2. C₆H₅OCH₃ ?

18. Carry out the conversions

(i) Propene to propan-1-ol (ii) Ethanol to but-1-yne

19. Copper crystallizes into a FCC lattice with edge length 3.61×10^-8cm. Show that the calculated density is in agreement with its measured value of 8.92gm/cm³. (Atomic mass of Copper = 63.5).

20. When a solution is prepared , 100kJ of heat energy is released. What type of deviation will the solution show from Raoult’s law? Explain with a graph and give an example of such a solution.

21. The decomposition of PH ₃ proceeds according to the reaction

4 PH₃ P₄ + 6 H₂

It is found that the rate of reaction follows the rate equation, rate=k[PH₃]. The half-life of PH₃ is 37.9 s at 120 ⁰C.

(i) How much time is required to decompose ¾ th of initial PH₃?

22. (i) Co²⁺ is stable in aqueous solution but in the presence of complexing agents get oxidized to Co³⁺.

(ii) Cu(I) is highly unstable in solutions

(iii) Zr and Hf have same properties.

23. Differentiate between antiseptics and disinfectants? Give one substance which acts both as antiseptic and disinfectant.

24. A metal ion M ⁿ⁺ having d⁴ valence electronic configuration combines with three didentate ligands to form a complex. Assume ₀ >P

(i) Draw diagram showing d orbital splitting during this complex formation

(ii) Write the electronic configuration of the valence electron of the metal ion in terms of t_2g and e_g.

(iii) Name the type of isomerism exhibited by this complex.

25. Account for the following-

(i) pKb of aniline is more than ethyl amine

(ii) Tertiary amines do not give acylation reactions.

(iii) Sulphanilic acid is insoluble in water but soluble in aqueous bases and aqueous acid taken separately.

26. Explain free radical polymerization of ethylene.

OR

How is Nylon-6 is prepared? What is indicated by 6 in Nylon-6?

27. Identify and name the following

(i) Building blocks of protein which must be supplied in the diet

(ii) Storage form of carbohydrates in animals

(iii) Water soluble vitamin that can be stored.

28. (i) State and explain Kohlrausch’s law.

(ii)For the cell reaction 2Fe³⁺ + 2I^- Fe²⁺ + I₂ (E⁰ cell = 0.236 at 298K). Calculate

G and K.

OR

(i) What is a fuel cell? Write the reactions taking place at cathode and anode of

H₂-O₂ fuel cell.

(ii) Write Nernst equation and calculate emf of the cell:

Fe_(s)/ Fe²⁺ (0.001M) || H⁺_(1M)/H_2(g)(1 bar)/Pt_(s) E⁰ _Fe2+/Fe = -0.44V.

29. Identify A to E and write the reactions involved.

Mg CO₂ H₂O i.Cl₂/P NH₃

CH₃Br A B C D E

ii. H₂O

OR

A compound A with molecular formula C₅H₁₀O gave a positive 2,4-DNP test but negative Tollen’s and iodoform test It was oxidized to carboxylic acid B with molecular formula C₃H₆O₂ when treated with alkaline KMnO₄ under vigorous oxidation. Sodium salt of B gave a hydrocarbon C on Kolbe’s electrolyte method. Identify A,B,C and write the reactions involved.

30. An element ‘A’ exists as a yellow solid in standard state. It forms a volatile hydride ‘B’ which is a foul smelling gas and is extensively used in qualitative analysis of salts. When treated with oxygen, ‘B’ forms an oxide ‘C’ which is a colourless, pungent smelling gas. This gas when passed through acidified KMnO₄ solution, decolourises it. ‘C’ gets oxidized to another oxide ‘D’ in the presence of a heterogeneous catalyst. Identify A,B,C,D and also give the chemical equation of reaction of ‘C’ with acidified KMnO₄ solution and for conversion of ‘C’ to ‘D’. [5]

OR

(a) Complete the following reactions:

(i) XeF₄ + PF₅ ?

(ii)U + 3ClF₃ ?

(iii) Ca₃P₂ + H₂O ?

(b) Give the structures of pyrophosphoric acid and XeO₃.

**********************

The major portion is  from

Unit 16: Chemistry in Everyday Life - ANTIOXIDANTS

Antioxidants are one of the important and necessary food additives. These compounds retard the action of oxygen on food thus reducing its speed of decomposition by oxidation. Hence they help in the preservation of food. These act as sacrificial materials, i.e. these are more reactive towards oxygen than are the materials they are protecting. They also reduce the rate of involvement of free radicals in the aging process.
Examples: The two most familiar antioxidants used are butylated hydroxy toluene (BHT) and butylated hydroxy anisole (BHA) (Figure 1). These phenolic compounds are added to preserve fats in packaged food. Oxygen reacts preferentially with BHA or BHT rather than oxidizing fats or oils, thereby protecting them from spoilage. The addition of BHA to butter increases its storage life from months to years. Sometimes, BHT and BHA are added in combination with citric or ascorbic acids to produce a more active synergetic
effect.

Sulphur dioxide and sulphites ( such as sodium sulphite, sodium bisulphite and sodium metabisulphite) are useful antioxidants for wine and beers, sugars syrups and cut, peeled or dried fruits and vegetables. They prevent or reduce their discoloration.

Questions from the section

1. Name one antioxidant commonly used to increase the storage life of butter.
2. Name one antioxidant used in wine and beers.

In general, the students are supposed to learn all topics as per CBSE Curriculum 2012.( chemistry_syllabus_2012_for_class_12 )

But, some teachers use to teach related portions also while taking a lesson. (There is no harm in it.)

However, for exam oriented study, such portions may be safely excluded for preparing for AISSCE Chemistry 2012; for example “Preparation of Hydrochloric Acid”

Don’t get panic. Learn all topics as per the CBSE Curriculum Document 2012. Available for download at chemistry_syllabus_2012_for_class_12 or cbse.nic.in

I feel it better to ask, what to study rather than what not!

SEE THE LIST BELOW and check whether yoou have revised them or not

The important portions are given emphasized

CHAPTER 1 - : Solid State

Classification of solids based on different binding forces:

molecular, ionic, covalent and metallic solids,

amorphous and crystalline solids (elementary idea),

Crystal Lattices and unit cells,
calculation of density of unit cell,

packing in solids,voids,

number of atoms per unit cell in a cubic unit cell,

point defects, electrical and magnetic properties.

CHAPTER 2 - Solutions

Types of solutions,

expression of concentration of solutions of solids in liquids,

solubility of gases in liquids,

solid solutions,

colligative properties – relative lowering of vapour pressure,

elevation of boiling point,

depression of freezing point,

osmotic pressure,

determination of molecular masses using colligative properties,

abnormal molecular mass.

CHAPTER 3 - Electrochemistry

Redox reactions,

conductance in electrolytic solutions,

specific and molar conductivity,

variations of conductivity with concentration,

Kohlrausch’s Law,

electrolysis and law of electrolysis (elementary idea),

dry cell -electrolytic cells and Galvanic cells,

lead accumulator,

EMF of a cell,

standard electrode potential,

Nernst equation and its application to chemical cells,

fuel cells

CHAPTER 4 - Chemical Kinetics

Rate of a reaction (Average and instantaneous),

factors affecting rate of reaction: concentration, temperature, catalyst order and molecularity of a reaction, rate law and specific rate constant,

integrated rate equation and half life (only for zero and first order reactions),

collision theory (elementary idea, no mathematical treatment).

CHAPTER 5 - Surface Chemistry

Adsorption – physisorption and chemisorption,

factors affecting adsorption of gases on solids,
colloids distinction between true solutions,

colloids and suspension; lyophilic , lyophobic multimolecular and macromolecular colloids;

properties of colloids; Tyndall effect,

Brownian movement, electrophoresis, coagulation,

emulsion – types of emulsions

CHAPTER 6 - General Principles and Processes of Isolation of Elements

Principles and methods of extracting – concentration, oxidation, reduction – electrolytic method and refining; occurrence and principles of extraction of aluminium, copper, zine and iron

CHAPTER 7 - p -Block Elements

(THIS IS THE MOST DISCUSSED UNIT REGARDING EXCLUDED PORTIONS. BUT WATCH THE SYLLABUS CAREFULLY, whether the discussed portions were really included or not. If it is not at all included from the beginning, what is the point of discussing excluded portions)

Group -15 Elements: General introduction, electronic configuration, occurrence, oxidation states, trends in physical and chemical properties; compounds of nitrogen: preparation and properties of ammonia and nitric acid, Phosphorous – allotropic forms, compounds of phosphorous: preparation and properties of phosphine, halides (PCI3, PCI5) and oxoacids (elementary idea only).
Group 16 Elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties, simple oxides, Ozone, Sulphure -allotropic forms; compounds of sulphur:

sulphuric acid: industrial process of manufacture, properties and uses,

oxoacids of sulphure (Structures only).
Group 17 Elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; compounds of halogens, hydrochloric acid, interhalogen compounds, oxoacids of halogens (structures only).
Group 18 Elements: General introduction, electronic configuration, occurrence, trends in physical and chemical properties, uses.

** Please see that the preparation of hydrochloric acid is not mentioned in syllabus. Only the Physical and Chemical properties are reqiuired**

CHAPTER 8 - d and f Block Elements

General introduction, electronic configuration, occurrence and characteristics of transition metals, general trends in properties of the first row transition metals – metallic character, ionization enthalpy, oxidation states, ionic radii, colour, catalytic property, magnetic properties, interstitial compounds,
alloy formation, preparation and properties of K2Cr2O7 and KMnO4.

Lanthanoids – Electronic configuration, oxidation states and lanthanoid contraction.
Actinoids – Electronic configuration, oxidation states.

CHAPTER 9 -  Coordination Compound

Coordination compounds – Introduction, ligands, coordination number, colour, magnetic properties and shapes, IUPAC nomenclature of mononuclear coordination compounds. Bonding, isomerism, importance of coordination compounds (in qualitative analysis, extraction of metals and biological system).

CHAPTER 10 - Haloalkanes and Haloarenes.

Haloalkanes: Nomenclature, nature of C -X bond, physical and chemical properties, mechanism of substitution reactions.

Haloarenes: Nature of C -X bond, substitution reactions (Directive influence of halogen in monosubstituted compounds only)
Uses and environmental effects of – trichloromethane, tetrachloromethane, iodoform.

CHAPTER 11 - Alcohols, Phenols and Ethers

Alcohols: Nomenclature, methods of preparation, physical and chemical properties( of primary alcohols only), identification of primary, secondary and tertiary alcohols, mechanism of dehydration, uses of methanol and ethanol.

Phenols: Nomenclature, methods of preparation, physical and chemical properties, acidic nature of phenol, electrophillic substitution reactions, uses of phenols.
Ethers: Nomenclature, methods of preparation, physical and chemical properties, uses

(Don’t leave any portions from here)

CHAPTER 12 - Aldehydes, Ketones and Carboxylic Acids

Aldehydes and Ketones: Nomenclature, nature of carbonyl group, methods of preparation, physical and chemical properties, mechanism of nucleophillic addition, reactivity of alpha hydrogen in aldehydes: uses.
Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical properties; uses.

(Don’t leave any portions from here)

CHAPTER 13 - Organic compounds containing Nitrogen

Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, identification of primary, secondary and tertiary amines.
Cyanides and Isocyanides – will be mentioned at relevant places in context.
Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry

CHAPTER 14 - Biomolecules

Carbohydrates – Classification (aldoses and ketoses), monosaccahrides (glucose and fructose), oligosaccharides (sucrose, lactose, maltose), importance.

Proteins -Elementary idea of  - amino acids, peptide bond, polypeptides, proteins, structure of proteins – primary,s econdary, tertiary structure and quaternary structures (qualitative idea only), denaturation of proteins.
Vitamins – Classification and functions.
Nucleic Acids: DNAand RNA.

CHAPTER 15 - Polymers

Classification – natural and synthetic, methods of polymerization (addition and condensation), copolymerization, some important polymers: natural and synthetic like polythene, nylon polyesters, bakelite, rubber.

CHAPTER 16 - Chemistry in Everyday life

Chemicals in medicines – analgesics, tranquilizers, antiseptics, disinfectants, antimicrobials, antifertility drugs, antibiotics, antacids, antihistamines.
Chemicals in food – preservations, artificial sweetening agents.
Cleansing agents- soaps and detergents, cleansing action.

(Don’t leave any portions from here)

WISH YOU ALL THE BEST