CBSE Class 12 Chemistry
General Instructions:
All questions are compulsory.
Questions number 1 to 5 are very short answer questions and carry 1 mark each.
Questions number 6 to 10 are short answer questions and carry 2 marks each.
Questions number 11 to 22 are also short answer questions and carry 3 marks each.
Question number 23 is a value based question and carry 4 marks.
Questions number 24 to 26 are long answer questions and carry 5 marks each.
Use log tables, if necessary. Use of calculators is not allowed.
1. Chemistry
1. What would be the nature of solid if there is no energy gap between valence band and
conduction band?
2. Which of the following reactions is SN1.type? =
3. Write the IUPAC name of the given compound:
4. On heating Copper turnings with conc. H2SO4 a colourless gas with pungent smell is evolved which decolourises acidified KMnO4 solution. Identify the gas with pungent smell.
5. Write the main reason for the stability of colloidal sols.
6. Show that the time required for completion of 3/4th of reaction of first order is twice that of half life (t1⁄2) of the reaction.
OR
Derive integrated rate equation for rate constant of a zero order reaction.
7. When a coordination compound PtCl4.6NH3 is mixed with AgNO3, 4 moles of AgCl are
precipitated per mole of the compound? Write:
i. Structural formula of the complex ii. IUPAC name of the complex
8. Write the structures of the following molecules:
i. H2 S2O8 ii. XeF6
9. An organic compound ‘X’ having molecular formula C4H8O gives orange-red ppt. with 2,4-DNP reagent. It does not reduce tollen’s reagent but gives yellow ppt. of iodoform on heating with NaOI. Compound X on reduction with LiAIH4 gives compound 'y' which undergoes dehydration reaction on heating with concH2S04 to form But-2-ene. Identify the compounds X and Y.
10. Write two differences between a solution showing positive deviation and a solution
showing negative deviation from Raoult’s law.
11. a. For the complex [CoF6]3-, write the hybridization type, magnetic character and spin nature of the complex. (At.number : Co=27) b. Why is the complex [Co(en)3]3+ more stable than the complex [CoF6]3-?
1. Chemistry
1. What would be the nature of solid if there is no energy gap between valence band and
conduction band?
2. Which of the following reactions is SN1.type? =
3. Write the IUPAC name of the given compound:
4. On heating Copper turnings with conc. H2SO4 a colourless gas with pungent smell is evolved which decolourises acidified KMnO4 solution. Identify the gas with pungent smell.
5. Write the main reason for the stability of colloidal sols.
6. Show that the time required for completion of 3/4th of reaction of first order is twice that of half life (t1⁄2) of the reaction.
OR
Derive integrated rate equation for rate constant of a zero order reaction.
7. When a coordination compound PtCl4.6NH3 is mixed with AgNO3, 4 moles of AgCl are
precipitated per mole of the compound? Write:
i. Structural formula of the complex ii. IUPAC name of the complex
8. Write the structures of the following molecules:
i. H2 S2O8 ii. XeF6
9. An organic compound ‘X’ having molecular formula C4H8O gives orange-red ppt. with 2,4-DNP reagent. It does not reduce tollen’s reagent but gives yellow ppt. of iodoform on heating with NaOI. Compound X on reduction with LiAIH4 gives compound 'y' which undergoes dehydration reaction on heating with concH2S04 to form But-2-ene. Identify the compounds X and Y.
10. Write two differences between a solution showing positive deviation and a solution
showing negative deviation from Raoult’s law.
11. a. For the complex [CoF6]3-, write the hybridization type, magnetic character and spin nature of the complex. (At.number : Co=27) b. Why is the complex [Co(en)3]3+ more stable than the complex [CoF6]3-?
i. Peptization ii. Zeta potential iii. Brownian movement
13. How do you convert:
i. Chlorobenzene to toluene ii. But-1-ene to But-2-ene iii. Ethanol to Ethyl iodide
OR
What happens when:
i. n-butyl chloride is treated with alcoholic KOH.
ii. 2-chloropropane is treated with sodium in the presence of dry ether.
iii. Chlorobenzene is treated with CH3Cl in the presence of anhydrous AlCl3.
14. Write the chemical equations involved in the above reactions.Write the principle behind
the following:
i. Vapour phase refining ii. Chromatography iii. Froth floatation process
15. i. Write the name of mono saccharides which are obtained after the hydrolysis of Lactose.
ii. What type of bonding is responsible for the stability of -helix ?
iii. Write the difference between Nucleotide and Nucleoside.
16. Give reasons:
i. The a-hydrogen atoms of aldehydes and ketones are acidic in nature.
ii. Oxidation of aldehydes is easier than ketones.
iii. CH2=CH-COOH is more acidic than CH3-CH2COOH.
17. Give reasons:
i. Red phosphorus is less reactive than white phosphorus.
ii. Sulphur shows greater tendency for catenation than oxygen.
iii. ClF3 is known but FCl3 is not known.
18. Complete the following reactions:
19. For the first order thermal decomposition reaction, the following data were obtained:
21. Write the name of monomers and their structures in the following:
i. Buna-S ii. Terylene iii. Nylon-6
22. An element crystallizes in a b.c.c lattice with cell edge of 400 pm. Calculate the density if 250 g of this element contain 2.5 x 1024 atoms ?
23. Due to hectic and busy schedule, Mr.Singh started taking junk food in the lunch break and slowly became habitual of eating food irregularly to excel in his field. One day during meeting he felt severe chest pain and fell down. Mr. Khanna, a close friend of Mr.Singh, took him to doctor immediately. The doctor diagnosed that Mr.Singh was suffering from acidity and prescribed some medicines. Mr.Khanna advised him to eat home made food and change his lifestyle by doing Yoga, meditation and some physical exercise. Mr.Singh followed his friend’s advice and after few days he started feeling better. After reading the above passage, answer the following:
i. What are the values (at least two) displayed by Mr.Khanna?
ii. What are antacids? Give one example.
iii. Would it be advisable to take antacids for a long period of time? Give reason.
24. a. Account for the following:
i. Mn2O7 is acidic whereas MnO is basic. ii. Zr and Hf exhibit similar properties.
iii. Transition metals form a large number of complex compounds.
b. Write type of the preparation of K2MnO4 from pyrolusite ore (MnO4).Write the type of magnetism shown by KMnO4 and K2MnO4
OR
a. The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co Ni Cu Zn
Answer the following:
i. Copper has exceptionally positive Eo (M2 + M) value Why?
ii. Which element is a strong reducing agent in +2 oxidation state and why?
iii.Zn2+ salts are colorless. Why?
b. Write the preparation of sodium dichromate from chromite ore (FeCr2O4).
25. a. Write the product(s) in each of the following reactions:
b. Write the chemical equations involved in the following reactions:
i. Reimer-Tiemann reaction ii. Friedal-Crafts alkylation of anisole.
OR
a. What happens when:
i. Phenol reacts with conc. HNO3 ii. Salicylic acid reacts with (CH3CO)2O/H+ iii. Ethyl chloride reacts with NaOCH3. Write the chemical equations involved in the above reactions.
b. Distinguish between:
i. Ethanol and Phenol ii. Propan-2-ol and 2-methylpropan-2-ol
26. a. Calculate ΔG° and log Kc for the following reaction at 298 K:
2Al(s) + 3Cu2+(aq) → 2Al3+(aq) +3Cu(s)
Given: E°cell=2.02 V
b. Using the Eo values of A and B, predict which is better for coating the surface of iron[Eo(Fe2+/Fe)=-0.44 V] to prevent corrosion and why ?
Given: E0(A2+/A)=-2.37 V : Eo(B2+/B)=-0.14 V
OR
a. The conductivity of 0.001 Calculate mol L-1solution of its molar conductivity CH3COOH is
3.90 x10-5Scm-1.degree is of dissociation(a).
Given λ ° (H+)=349.6 S cm2 mol-1 and λ ° (CH3COO-)=40.9 S cm2 mol-1
b. What type of battery is dry cell? Write the overall reaction occurring in dry cell.
2. Chemistry
1. What is the maximum possible coordination number of an atom in an hcp crystal structure of anπelement? [1]
2. State the formula relating pressure of a gas with its mole fraction in a liquid solution in contact with it. [1]
3. Express the relation between the half-life period of a reactant and its initial concentration if the reaction involved is of second order. [1]
4. How are formalin and trioxane related to methanol? [1]
5. Why are primary amines higher boiling than tertiary amines? [1]
6. Show that the Heisenberg Uncertainty Principle is of negligible significance for an object of
10-6 kg mass. (h/4π =0.528 x 10-34 kg m2s-1)
OR
On the basis of Heisenberg Uncertainty Principle show that the electron ( mass= 9 x 10-31kg cannot exist within an atomic nucleus of radius 10-15m. [2]
7. On the basis of the following values at1073K:
S2(s) + 2O2(g) ⟶2SO2(g); ∆Go = -544 kj mol-1
2Zn(s) + O2(g) ⟶2ZnO(s); ∆Go = -480 kj mol-1
2Zn(s) + S2(s) ⟶2ZnS(s); ∆Go = -293 kj mol-1
Show that the roasting of zinc sulphide to form zinc oxide is a spontaneous process. [2]
8. Write one chemical reaction each to show that (a) Tin (II) chloride is a reducing agent. (b) Chlorine gas can be obtained from bleaching powder. [2]
9. Describe the steps involved in the preparation of either potassium dichromate from sodium chromate or potassium permanganate from manganese dioxide. [2]
10. What are enantiomers and diastereomers? Differentiate between chiral and achiral molecules. [2]
11. Give an illustration of Reimer-Thiemann reaction. [2]
12. How bakelite made and what is is its major use? Why is bakelite a thermo-setting polymer'. [2]
13. (a) What is meant by linear combination of atomic orbital?
(b) Illustrate bonding and ant bonding molecular orbital based on bomb-nuclear dihydrogen molecule. [3]
OR
What kinds of molecular forces are expected to exist between the species in any three of the following pairs constituting mixtures?
(a) He and N2
(b) Cl2 and NO
(c) NH3 and CO2
(d) H2S and HBr
14. Aluminium metal forms a cubic close-packed crystal structure. Its atomic radius is 125 x 10-12m.
(a) Calculate the length of the side of the unit cell.
(b) How many such unit cells are there in 1.00 m 3 of aluminium? [3]
15. A solution is made by dissolving 30 g of a non-volatile solute in 90 g of water. It has a
vapor pressure of 2.8 kPa at 298 K. At 298 K, vapor pressure of pure water is 3.64 kPa.
Calculate the molar mass of the solute. [3]
16. Comment on the validity of the following statements, giving reasons: [3]
(a) Thermodynamically an exothermic reaction is sometimes not spontaneous.
(b) The entropy of steam is more than that of waterat its boiling point.
(c) The equilibrium constant for a reaction is one or more if ∆Go for it is less than zero.
17. A first order reaction takes 69.3 minutes for 50% completion. Set up an equation for
determining the time needed for 80% completion of this reaction. (Calculation of result is not
required). [3]
18. Illustrate with examples: [3]
(a) Lyophilic and Lyophobic sols
(b) Multimolecular and Macromolecular colloids
(c) Homogeneous and Heterogeneous catalysis.
19. The Eo values in respect of electrodes of chromium (Z = 24), manganese (Z = 25) and
iron (Z =26) are: [3]
Cr3+/Cr2+ = -0.4V; Mn3+/Mn2+ = +1.5v, Fe3+ = +0.8V
On the basis of the above information compare the feasibility of further oxidation of their
+2 oxidation states.
20. Draw a sketch to show the splitting of orbital inan octahedral crystal field. State for a d6
ion how the actual configuration of the split d-orbital in an octahedral crystal field is decided
by the relative values △u of and P. [3]
21. (a) Write the structural formula of 3-phenylprop-2-enal.
(b) Write one chemical equation each to illustrate the following reactions:
(i) Aldol condensation (ii) Cannizzaro's reaction [3]
22. (a) Assign a reason for each of the following statements:
(i) Alkylamines are stronger bases than arylamines.
(ii) Acetonitrile Is preferred as solvent for carrying out several organic reactions.
(b) How would you convert methylamine into ethylamine? [3]
23. When the nuclides 27/13Al, 24/12Mg, and 27/14 Si are separately subjected to [∝,n ] nuclear reactions, three separate new nuclides are produced, each of which further undergoes one
positron emission finally giving stable nuclei. Write the nuclear equations for the reactions
involved in these cases. [3]
24. (a) State the function along with one example each of: [3]
(i) Antihistamines
(ii) Antioxidants
(b) What are hybrid propellants?
25. (a) Define electrical conductivity and molar conductivity of a solution and write the units
of molar conductivity.
(b) The Eo values corresponding to the following two reduction electrode processes are:
Cu+/Cu = +0.52V
Cu2+/Cu+ = 0.16V
Formulate the galvanic cell for their combination. What will be the standard cell potential
for it? Calculate ∆Go for the cell reaction. [5]
Or
(a) In the button cell, widely used in watches and other devices, the following reaction takes
place:
Zn(s) + Ag2O(s) + H2O(f) ⟶Zn2+(aq) + 2Ag(s) + 2OH- (aq)
Determine Eo and ΔG°for the reaction.
Given Eo Ag+ / Ag = +0.80V, Eo Zn+ / Zn = -0.76V
(b) Explain with examples the terms weak and strong electrolytes. How can these be
distinguished? [5]
26. (a) Assign an appropriate reason for each of the following statements:
(i) SiF2-6is known but SiCl2-6is not known.
(ii) More metal fluorides are ionic in nature than metal chlorides.
(iii) Solid phosphorus pentachloride exhibits some ionic character.
(b) Write the structural formulae for the following: [3, 2]
(i) BrF3
(ii) XeOF4
Or
(a) Assign a reason for each of the following:
(i) In group 14 the tendency for catenation decreases with increasing atomic numbers.
(ii) In group 15 the bond angle H - M - H decreases in the following order
NH3(107.8o ), PH3(93.6o ),AsH3(91.8o )
(iii) Sulphur hexafluoride is used as a gaseous electrical insulator.
(b) Complete the following reaction equations: [3, 2]
(i)R2SiCl2 + H2O
(ii)XeF4 + H2O
27. (a) Write chemical equations for the reactions of glucose with
(i) acetic anhydride and
(ii) ammoniacal silver nitrate solution.
(b) Draw simple Fischer projections of D-glucose and L-glucose.
(c) What do you understand by replication by DNA? How does DNA differ from RNA
structurally? [2, 1, 2]
Or
(a) Write the following about protein synthesis:
(i) Name the location where protein synthesis occurs.
(ii) How do 64 codons code for only 20 amino acids?
(ii) Which of the two bases of the codon are most important for coding?
(b) What deficiency diseases are caused due to lack of vitamins A, B, B6 and K in human diet?[3, 2]
3. Chemistry
1. What is the reason for the stability of colloidal solution?
2. Give an example each of a molecular solid and an ionic solid.
3. Pb(NO3)2 on heating gives a brown gas which undergoes dimerization on cooling?Identify the gas.
4. Write the structure of an isomer of compound C4H9Br which is most reactive towards SN1
reaction.
5. Write the IUPAC name of the given compound:
6. When a coordination compound Co is mixed with AgNO3,3 moles of AgCl are precipitated per mole of the compound. Write i. Structural formula of the complex ii. IUPAC name of the complex
7. i. Gas (A) is more soluble in water than Gas (B) at the same temperature. Which one of the two gases will have the higher value of KH (Henry’s constant) and why? ii. In non-ideal solution, what type of deviation shows the formation of maximum boiling azeotropes?
Write the structures of the following:
(i) BrF3 (ii) Xe
8. What happens when: i. SO2 gas is passed through an aqueous solution salt? ii. XeF4 reacts with SbF5 ?
9. Write the chemical equations involved in the following reactions:
i. Hoffmann-bromamide degradation reaction ii. Carbylamine reaction
10. For a reaction: H2 + Cl2 ➝2HCl Rate=k
10. For a reaction: H2 + Cl2 ➝2HCl Rate=k
i. Write the order and molecularity of this reaction. ii. Write the unit of k.
11. a. For the complex [Fe(H2O)6]3+ , write the hybridization, magnetic character and spin of
the complex. (At. number: Fe=26) b. Draw one of the geometrical isomers of the complex [Pt(en)2Cl2]2+ which is optically inactive.
12. i. Write the structural difference between starch and cellulose.
ii. What type of linkage is present in Nucleic acids?
iii. Give one example each for fibrous protein and globular protein.
13. i. What is the role of Sulphur in the vulcanization of rubber?
ii. Identify the monomers in the following polymer:
iii. Arrange the following polymers in the increasing order of their intermolecular forces:
Terylene, Polythene, Neoprene
14. How do you convert: Write the major product(s) in the following:
i. Chlorobenzene to biphenyl ii. Propene to 1-iodopropane iii. 2-bromobutane to but-2-ene
15. Give reasons for the following:
i. Aniline does not undergo Friedal-Crafts reaction.
ii. (CH3)2 NH is more basic than (CH3)3 N in an aqueous solution.
iii. Primary amines have higher boiling point than tertiary amines.
17. Give reasons:
i. SO2 is reducing while TeO2 is an oxidizing agent.
ii. Nitrogen does not form pentahalide.
iii. ICl is more reactive than I2.
18. Calculate the boiling point of solution when 4 g of MgSO4 (M=120 g mol-1) was dissolved
in 100 g of water, assuming MgSO4 undergoes complete ionization.( for water50.52 K kg mol-1)
19. i. Name the method of refining of nickel
ii. What is the role of cryolite in the extraction of aluminium?
iii. What is the role of limestone in the extraction of iron from its oxides?
20. Define the following terms: i. Lyophilic colloid ii. Zeta potential iii. Associated colloids
21. For the first order thermal decomposition reaction, the following data were obtained:
C2H5Cl(g)→C2H4(g)+HCl(g)
Time/sec Total pressure / atm
0 0.30 300 0.50
Calculate the rate constant
(Given: log 2=0.301, log 3=0.4771, log 4=0.6021)
22. An element crystallizes in a b.c.c. lattice with cell edge of 500pm. The density of the
element is 7.5g cm-3. How many atoms are present in 300 g of the element?
23. Due to hectic and busy schedule, Mr. Singh started taking junk food in the lunch break
and slowly became habitual of eating food irregularly to excel in his field. One day during
meeting he felt severe chest pain and fell down. Mr. Khanna, a close friend of Mr. Singh.
took him to doctor immediately. The doctor diagnosed that Mr. Singh was suffering from
acidity and prescribed some medicines. Mr. Khanna advised him to eat homemade food
and change his lifestyle by doing yoga, meditation and some physical exercise. Mr. Singh followed his friend’s advice and after few days he started feeling better. After reading the above passage, answer the following:
i. What are the values (at least two) displayed by Mr. Khanna?
ii. What are antacids? Give one example.
iii. Would it be advisable to take antacids for a long period of time? Give reason.
24. Account for the following:
1. Mn shows the highest oxidation state of +7 with oxygen but with fluorine it shows
the highest oxidation state of +4.
2. Cr2+ is a strong reducing agent.
3. Cr2+ salts are coloured while Zn2+ salts are white.
OR
a. The elements of 3d transition series are given as:
Sc Ti V Cr Mn Fe Co Ni Cu Zn
b. Answer the following:
i. Write the element which shows maximum number of oxidation states.Give reason.
ii. Which element has the highest m.p?
iii. Which element shows only +3 oxidation state?
iv. Which element is a strong oxidizing agent in +3 oxidation state and why?
25. a. Write the structures of A and B in the following reactions:
i. CH3COCl
ii. CH3MgBr
b. Distinguish between:
i. C6H5-COOH3 and C6H5-CHO
ii. CH3COOH and HCOOH
c. Arrange the following in the increasing order of their boiling points:
CH3CHO, CH3COOH, CH3CH2OH
OR
a. Write the chemical reaction involved in Wolff-Kishner reduction.
b. Arrange the following in the increasing order of their reactivity towards nucleophilic
addition reaction:
C6H5COCH3, CH3-CHO, CH3COC
c. Why carboxylic acid does not give reactions of carbonyl group?
d. Write the product in the following reaction CH3CH2CH=CH2CH
e. A and B are two functional isomers of compoundC3H6O. On heating with NaOH and I2, isomer B forms yellow precipitate of iodoform whereas isomer A does not form any precipitate. Write the formulae of A and B.
26. a. Calculate E°cell for the following reaction at 298K:
2Al(s)1+3Cu2+ (0.01M) →2A]3+(0.01M)+ 3Cu(s) Given: Ecell =1.98 V
2Al(s)1+3Cu2+ (0.01M) →2A]3+(0.01M)+ 3Cu(s) Given: Ecell =1.98 V
b. Using the E° values of A and B, predict which is better for coating the surface of iron[E°(Fe2+ /Fe) =-0.44V] to prevent corrosion and why? Given: E° (A2+ /A) =-2.37V: E° B2+ /B) =-0.14V
OR
a. The conductivity of 0.001 mol L-1solution of CH3COOH is 3.905x10-5S cm-1calculateits
molar conductivity and degree of dissociation (∝).Given (H+ ) =349.6 S mol-1 and (CH3COO-)=40.9 S mol-1
b. Define electro chemical cell. What happens if external potential applied becomes greater than E°cell of electro chemical cell?
4. CHEMISTRY
1. On heating Zn granules with conc. HNO3, a brown gas is evolved which undergoes dimerization on cooling. Identify the gas.
2. What is the reason for the stability of colloidal sols?
3. Write the IUPAC name of the given compound:
4. Out of CH2=CH CH2Cl and CH3CH2-CH2Cl, which is more reactive towards SN1 reaction?
5. What type of magnetism is shown by a substance if its domains are arranged in equal number and in opposite directions?
6. When a coordination compound PdCl24NH3is mixed with AgNO3, 2 moles of AgCl are
precipitated per mole of the compound. Write:
(i) Structural formula of the complex (ii) IUPAC name of the complex
7. Write the chemical equations involved in the following reactions:
(i) Clemmensen reduction (ii) Hell-Volhard Zelinsky reaction
OR
How do you convert
(i) Toluene to benzaldehyde (ii) Ethanoyl chloride to ethanal
8. For a reaction: 2NH3(g) →(g)+ 3H2(g) Rate=k
(i) Write the order and molecularity of this reaction.(ii) Write the unit of k.
9. For the given cells:
Lead storage cell, Mercury cell, Fuel cell and Dry cell
Answer the following:
(i) Which cell is used in hearing aids?
(ii) Which cell was used in Apollo space programme?
(iii) Which cell is used in automobiles and inverters?
(iv) Which cell does not have long life?
10.When pyrolusite ore MnO2is fused with KOH in presence of air, a green coloured compound (A) is obtained which undergoes disproportionation reaction in acidic medium to give a purple coloured compound (B):
(i) Write the formulae of the compounds (A) and (B).
(ii) What happens when compound (B) is heated?
11. Calculate E0cell for the following reaction at 298K:
2Cr(s) +3Fe2+(0.01M) →2Cr3(0.01M)+3Fe(s)
Given: Ecell=261 V
12. (i) Name the method of refining Zirconium.(ii) In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
4. CHEMISTRY
1. On heating Zn granules with conc. HNO3, a brown gas is evolved which undergoes dimerization on cooling. Identify the gas.
2. What is the reason for the stability of colloidal sols?
4. Out of CH2=CH CH2Cl and CH3CH2-CH2Cl, which is more reactive towards SN1 reaction?
5. What type of magnetism is shown by a substance if its domains are arranged in equal number and in opposite directions?
6. When a coordination compound PdCl24NH3is mixed with AgNO3, 2 moles of AgCl are
precipitated per mole of the compound. Write:
(i) Structural formula of the complex (ii) IUPAC name of the complex
7. Write the chemical equations involved in the following reactions:
(i) Clemmensen reduction (ii) Hell-Volhard Zelinsky reaction
OR
How do you convert
(i) Toluene to benzaldehyde (ii) Ethanoyl chloride to ethanal
8. For a reaction: 2NH3(g) →(g)+ 3H2(g) Rate=k
(i) Write the order and molecularity of this reaction.(ii) Write the unit of k.
9. For the given cells:
Lead storage cell, Mercury cell, Fuel cell and Dry cell
Answer the following:
(i) Which cell is used in hearing aids?
(ii) Which cell was used in Apollo space programme?
(iii) Which cell is used in automobiles and inverters?
(iv) Which cell does not have long life?
10.When pyrolusite ore MnO2is fused with KOH in presence of air, a green coloured compound (A) is obtained which undergoes disproportionation reaction in acidic medium to give a purple coloured compound (B):
(i) Write the formulae of the compounds (A) and (B).
(ii) What happens when compound (B) is heated?
11. Calculate E0cell for the following reaction at 298K:
2Cr(s) +3Fe2+(0.01M) →2Cr3(0.01M)+3Fe(s)
Given: Ecell=261 V
12. (i) Name the method of refining Zirconium.(ii) In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
(iii) What is the function of limestone in the extraction of iron from its oxides?
13. (i) Out of silica gel and anhydrous CaCl2, which will adsorb the water vapours?
(ii) Out of H2SO4 and H3PO4, which one is more effective in causing coagulation of positively
charged sol? Give reason.
(iii) Out of sulphur sol and proteins, which one forms macromolecular colloids?
14. The rate constant for the first order decomposition of H2O2 is given by the following equation:
log k =14.2 1.0 x 10 4 K
T
Calculate Ea for this reaction and rate constant k if its half - life period be 200 mintues.(Given: R=8.314 JK-1 mole-1)
15. An element crystallizes in a f.c.c. lattice with cell edge of 400 pm. The density of theelement is 7g cm-3. How many atoms are present in 280 g of the element?
16. (a) For the complex [CoF6]3-, write the hybridization, magnetic character and spin of the complex. (At. number: Co=27)
(b) Draw one of the geometrical isomers of the complex [Co(en)2CI2]+ which is optically active.
17. (i) Write the name of two monosaccharides obtained on hydrolysis of maltose sugar.
(ii) Name the vitamin whose deficiency causes convulsions.
(iii) Write one example each for Fibrous protein and Globular protein.
18. (i) What is the role of t-butyl peroxide in the polymerization of ethene?
(ii) Identify the monomers in the following polymer:
(iii) Arrange the following polymers in the increasing order of their intermolecular forces:
PVC, Nylon-6, Buna-N
OR
Write the mechanism of free radical polymerization of ethene.
19. Complete the following reactions:
20. Give reasons for the following:
(a) Aldehydes (R-CHO) are more reactive than ketones (R-CO-R) towards nucleophilic addition
reaction.
(b) Benzaldehyde does not undergo aldol condensation reaction.
(c) Benzoic acid does not give Friedal-Crafts reaction.
21. What happens when: (i) 2, 4, 6 - trinitrochlorobenzene is treated with warm water.
(ii) 2-chlorobutane is treated with alcoholic KOH.
(iii) ethyl chloride is treated with Na metal in presence of dry ether. Write the equation involved in the above reactions.
22. Give reasons:
(i) Mn shows the highest oxidation state of 17 with oxygen but with fluorine it shows the
highest oxidation state of 14. (ii) Zn is soft whereas Cr is hard. (iii) Eu2+ is a good reducing agent.
23. Due to hectic and busy schedule, Mr. Awasthi made his life full of tensions and anxiety.
He started taking sleeping pills to overcome the depression without consulting the doctor.Mr. Roy, a close friend of Mr. Awasthi, advised him to stop taking sleeping pills and suggested to change his lifestyle by doing Yoga, meditation and some physical exercise. Mr. Awasthi followed his friend’s advice and after few days he started feeling better. After reading the above passage, answer the following:
(i) What are the values (at least two) displayed by Mr. Roy?
(ii) Why it is not advisable to take sleeping pills without consulting doctor?13. (i) Out of silica gel and anhydrous CaCl2, which will adsorb the water vapours?
(ii) Out of H2SO4 and H3PO4, which one is more effective in causing coagulation of positively
charged sol? Give reason.
(iii) Out of sulphur sol and proteins, which one forms macromolecular colloids?
14. The rate constant for the first order decomposition of H2O2 is given by the following equation:
log k =14.2 1.0 x 10 4 K
T
15. An element crystallizes in a f.c.c. lattice with cell edge of 400 pm. The density of theelement is 7g cm-3. How many atoms are present in 280 g of the element?
16. (a) For the complex [CoF6]3-, write the hybridization, magnetic character and spin of the complex. (At. number: Co=27)
(b) Draw one of the geometrical isomers of the complex [Co(en)2CI2]+ which is optically active.
17. (i) Write the name of two monosaccharides obtained on hydrolysis of maltose sugar.
(ii) Name the vitamin whose deficiency causes convulsions.
(iii) Write one example each for Fibrous protein and Globular protein.
18. (i) What is the role of t-butyl peroxide in the polymerization of ethene?
(ii) Identify the monomers in the following polymer:
(iii) Arrange the following polymers in the increasing order of their intermolecular forces:
PVC, Nylon-6, Buna-N
OR
Write the mechanism of free radical polymerization of ethene.
19. Complete the following reactions:
20. Give reasons for the following:
(a) Aldehydes (R-CHO) are more reactive than ketones (R-CO-R) towards nucleophilic addition
reaction.
(b) Benzaldehyde does not undergo aldol condensation reaction.
(c) Benzoic acid does not give Friedal-Crafts reaction.
21. What happens when: (i) 2, 4, 6 - trinitrochlorobenzene is treated with warm water.
(ii) 2-chlorobutane is treated with alcoholic KOH.
(iii) ethyl chloride is treated with Na metal in presence of dry ether. Write the equation involved in the above reactions.
22. Give reasons:
(i) Mn shows the highest oxidation state of 17 with oxygen but with fluorine it shows the
highest oxidation state of 14. (ii) Zn is soft whereas Cr is hard. (iii) Eu2+ is a good reducing agent.
23. Due to hectic and busy schedule, Mr. Awasthi made his life full of tensions and anxiety.
He started taking sleeping pills to overcome the depression without consulting the doctor.Mr. Roy, a close friend of Mr. Awasthi, advised him to stop taking sleeping pills and suggested to change his lifestyle by doing Yoga, meditation and some physical exercise. Mr. Awasthi followed his friend’s advice and after few days he started feeling better. After reading the above passage, answer the following:
(i) What are the values (at least two) displayed by Mr. Roy?
(iii) What are tanquilizers? Give two examples.
24. (a) Write the product(s) in each of the following reactions:
(i) CH2=CH-CH2OH
(ii) 2CH3CH2OH
(iii)CH3CH2-O-CH2CH3
(b) Write the mechanism of the following reaction:
OR
(a) Write equations of the following reactions:
(i) Bromine in CS2 with phenol (ii) Treating phenol with chloroform in the presence of aq. NaOH
(iii) Anisole reacts with HI
(b) Distinguish between:
(i) Ethanol and Diethyl ether (ii) Propanol and t-butyl alcohol
25. (a) Calculate the boiling point of solution when 2g of Na2SO4(M=142 g mole-1 was dissolved in 50 g of water, assuming Na2SO4 undergoes complete ionization. (Kb for water=0.52 K kg mole-1)
(b) Define the following terms: (i) Colligative properties (ii) Ideal solution
OR
(a) When 2.56 g of sulphur was dissolved in 100 g of the freezing point lowered by 0.383 K.
Calculate the formula of sulphur (Sx).(Kf for CS2=3.83 K kg mol-1 Atomic mass of
Sulphur =32g mole-1)
(b) Blood cells are isotonic with 0.9% sodium chloride solution. What happens if we place blood cells in a solution containing?
(i) 1.2% sodium chloride solution
(ii) 0.4% sodium chloride solution
26. (a) Account for the following:
(i) H2Te is more acidic thanH2S. (ii) Cl5is more covalent than Cl3
(iii) Boiling points of interhalogens are little higher as compare to pure halogens.
(b) Draw the structures of:
(i) HClO4 (ii) XeOF4
OR
(i) Arrange the following in the increasing order of their reducing character:
(ii) Out of He and Xe, which one can easily form compound and why?
(iii) Write the conditions to maximize the yield of ammonia in Haber’s process.
(iv) Write two uses of Chlorine gas.
(v) How can you detect the presence of SO2 gas?
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