Time: 2 Hours <\/span> General Instructions to candidates:<\/span><\/p>\n Answer all questions from 1 to 7. Each question carries 1 score. (7 \u00d7 1 = 7)<\/span><\/p>\n Question 1. Question 2. Question 3. Question 4. Question 5. Question 6. Question 7. II. Questions from 8 to 20 carry 2 score each. Answer any 10 questions. (10 \u00d7 2 = 20)<\/span><\/p>\n Question 8. Question 9. Question 10. Question 11. Question 12. Question 13. Question 14. Question 15. Question 16. Question 17. Question 18. Question 19. Question 20. III. Questions from 21 to 29 carry 3 score each. Answer any 7 questions. (7 \u00d7 3 = 21)<\/span><\/p>\n Question 21. Question 22. Question 23. Question 24. b) Vapour phase refining c) The impure metal bar is heated at one end with moving circular heater. The heater is now slowly moved along the rod. The pure metal recrystallises from the melt while impurities remain in the melt. Finally the end where impurities have collected is cut off. The impure metal bar is heated at one end with moving circular heater. The heater is now slowly moved along the rod. The pure metal recrystallises from the melt while impurities remain in the melt. Finally the end where impurities have collected is cut off.<\/p>\n Question 25. Question 26. Question 27. Question 28. Consequences:<\/p>\n Question 29. IV. Questions from 30 to 33 carry 4 score each. Answer any 3. (3 \u00d7 4 = 12)<\/span><\/p>\n Question 30.
\nCool off time: 15 Minutes<\/span>
\nMaximum: 60 Score<\/span><\/p>\n\n
\nIf N spheres are there in a close packing, what is the total number of tetrahedral and octahedral voids present in it?
\nAnswer:
\nTetrahedral 2N, octahedral N<\/p>\n
\nWhat is the order of a reaction, if its half life is independent of initial concentration?
\nAnswer:
\n1st<\/sup> order<\/p>\n
\nWhat is the magnetic moment of an atom having d configuration.
\nAnswer:
\nZero<\/p>\n
\nGabriel synthesis of used forthe preparation of which type of amines?
\ni) Primary
\nii) Secondary
\niii) Tertiary
\niv) Quaternary
\nAnswer:
\ni) Primary<\/p>\n
\nWhich vitamin is responsible for blood clotting?
\nAnswer:
\nVitamin K<\/p>\n
\nName the linear polymer formed during the condensation polymerization between phenol and formaldehyde.
\nAnswer:
\nbakelite<\/p>\n
\nWhich is the chemical substance discovered by Paul Ehlrich for the treatment of syphilis?
\nAnswer:
\nSalvarsan or Arephenamine<\/p>\n
\nDraw the vapour pressure-mole fraction curve for a non-ideal solution having positive deviation, if A and B are the two volatile components.
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-1.png\")
<\/p>\n
\nCalculate the depression in freezing point of a 0.2 molal solution if kg for water is 1.86 K kg mol-1<\/sup>.
\nAnswer:
\n\u0394Tf<\/sub> = kj<\/sub>m
\n= 1.86 \u00d7 0.2
\n= 0.372K<\/p>\n
\nSuppose you are given a sample of NaCl salt. How will you prepare chlorine gas in laboratory using the above sample? (Write balanced chemical equations)
\nAnswer:
\nBy the electrolysis of sodium chloride solution Cl2<\/sub> gas can be prepared
\n2NaCl + 2H2<\/sub>O \u2192 2Na+<\/sup> + 2OH–<\/sup> + H2<\/sub>+<\/sup>(g)<\/sub> + Cl2(g)<\/sub><\/p>\n
\nGive one use each of Freon 12, DDT, CCl4and CHl3.
\nAnswer:
\nFreon – 12-Refrigerant
\nDDT – insecticide
\nCCl4<\/sub> – For the manufacture of refrigerant
\nCHl3<\/sub> – Antiseptic<\/p>\n
\nWrite equations showing Wurtz-Fittig reaction and Fittig reaction.
\nAnswer:
\nFitting reaction
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-2.png\")
<\/p>\n
\nIdentify A and B in the following equations:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-3.png\")
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-4.png\")
<\/p>\n
\nHow the conversion of carbon dioxide to carboxylic acid can be effected using. Grignard reagent?
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-5.png\")
<\/p>\n
\nComplete the following equations:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-6.png\")
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-7.png\")
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-8.png\")
<\/p>\n
\nDescribe primary and secondary structure of proteins.
\nAnswer:
\nStructure of proteins:
\n1) Primary structures – amino acids are arranged in sequence.
\n2) Secondary structure:
\na) \u03b1 – helix – polypeptide chains are coild to form a helical structure eg. Myosine
\nb) \u03b2-pleated structure: amino acid chains lie side by side and bonded by hydrogen bonds, eg. Keratine.<\/p>\n
\nExplain homopolymers and copolymers with examples.
\nAnswer:
\nPolymers formed by polymerisation of one type of monomer are called homopolymer, eg. Polythene Polymers formed by polymerisation 0 two or more different monomers are called copolymers eg. SBR, Rubber, Nylon 6, 6.<\/p>\n
\nBriefly explain different types of artificial sweetening agents.
\nAnswer:
\nCommonly used artificial sweetener is saccharin. It is 550 times sweeter than sucrose. Alitame is 1000 times sweet as cane sugar.
\nAspartame, monolellin etc are other sweetening agent.<\/p>\n
\nWrite the IUPAC names of the following compounds:
\na) [Ni(CO)4<\/sub>]
\nb) K3<\/sub>[Fe(C2<\/sub>O4<\/sub>)3<\/sub>]
\nAnswer:
\na) Ni(CO)4\u00a0<\/sub>Tetra carbonyl nickel (0)
\nb) K3<\/sub> [Fe(C2<\/sub>O4<\/sub>)3<\/sub>] Potassium tris oxalate ferrate iii<\/p>\n
\nDistinguish Ferromagnetism and Ferrimagnetism.
\nAnswer:
\nFerromagnetic substance – Magnetic moments are in one direction.
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-9.png\")
\nThey are strongly attracted my magnetic field, eg Fe, Co
\nFerrimagneticsubstances: Magnetic moments are unequal and in opposite direction.
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-10.png\")
\neg. Fe3<\/sub>O4<\/sub>, MgFe2<\/sub>O4<\/sub><\/p>\n
\nSilver atoms are arranged in CCP lattice structure. The edge length of its unit cell is 408 pm. Calculate the density of silver. (Atomic mass of silver is 108.4)
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-11.png\")
<\/p>\n
\nThe rate of a reaction quadruples when the temperature changes from 293 K to 313 K. Calculate the energy of activation of the reaction assuming that it does not change with temperature.
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-12.png\")
<\/p>\n
\nExplain any three chemical methods for the preparation of Lyophobic colloids with suitable examples.
\nAnswer:
\n1) Oxidation methods: Oxidation of aqueous solution of H2<\/sub>S with SO2<\/sub>
\nSO2<\/sub> + 2H2<\/sub>S \u2192 3S + 2H2<\/sub>O
\n2) Reduction method : Reduction of AuCl3<\/sub> solution using SnCl2<\/sub>
\n2AuCl3<\/sub> + 3SNCl2<\/sub> \u2192 3SnCl4<\/sub> + 2Au
\n3) Hydrolysis. By adding a saturated solution of ferric .chloride dropwise to a large excess of boiling water
\nFeCl3<\/sub>\u00a0+ 3H2<\/sub>O \u2192 Fe(OH)3<\/sub> + 3HCl<\/p>\n
\nExplain the following refining processes:
\na) Distillation
\nb) Vapour phase refining
\nc) Zone refining
\nAnswer:
\na) Distillation: The impure metal is heated to form pure metals as distillate it is collected and condensed impurities are left behind, eg Zn and Hg.
\nOnly metals with low boiling point can apply this method.<\/p>\n
\ni) Van Arkel method – eg Titanium, Zirconium, Thorium etc.
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-13.png\")
\nMond process: Nickel is strongly heated with carbon monoxide to form Nickel tetra carbonyl this is again heated strongly to get pure nickel.
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-14.png\")
<\/p>\n
\nA solution of CuSO4<\/sub> is electrolysed for 20 minutes with a current of 1.5 amperes. What is the mass of copper deposited at cathode?
\n(Atomic mass of copper – 63)
\nAnswer:
\nCu2+<\/sup> + 2e \u2192 Cu
\nQ = It\u00a0 \u00a01.5 \u00d7 20 \u00d7 60 = 1800 C
\nMass of Cu deposited by 1800 C
\n\\(\\frac{63.5 \\times 1800}{2 \\times 96500}\\) = 0.5875 g<\/p>\n
\nBriefly explain the manufacture of sulphuric acid by contact process.
\nAnswer:
\nContact Process
\n1) Sulphur is burnt in air to form Sulphur Dioxide
\nS + O2<\/sub> \u2192 SO2<\/sub>
\n2) Sulphur Dioxide is again oxidised to SO3<\/sub> with atmospheric oxygen in the presence of
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-15.png\")
\n3) SO3<\/sub> is treated with Sulphuric acid to get Oleum
\nSO3<\/sub> + H2<\/sub>SO4<\/sub> \u2192 H2<\/sub>S2<\/sub>O7<\/sub>
\n4) Oleum is diluted to get H2<\/sub>SO4<\/sub>
\nH2<\/sub>S2<\/sub>O7<\/sub> + H2<\/sub>O \u2192 2H2<\/sub>SO4<\/sub><\/p>\n
\nExplain with the help of equations, preparation of Xenon fluorides.
\nAnswer:
\nXe + F2<\/sub> \u2192 XeF2<\/sub>
\nXe + 2F2<\/sub> \u2192 XeF4<\/sub>
\nXe + 3F2<\/sub> \u2192 XeF6<\/sub><\/p>\n
\nDescribe lanthanoid contraction. Write any two consequences of it.
\nAnswer:
\nThe steady but slow decrease in the size of atoms or ions of the lanthanoids with increase in atomic number is called Lanthanoid Contraction.<\/p>\n\n
\nHow the conversion of an aldehyde to acetal can carried out?
\n(Write chemical equations)
\nAnswer:
\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-16.png\")
<\/p>\n
\nPredict the products of electrolysis of the following substances at anode and cathode using suitable chemical equations.
\na) Aqueous NaCl
\nb) H2<\/sub>SO4<\/sub> solution
\nAnswer:
\nElectrolysis of aqeous NaCl
\na) At Cathode H+<\/sup> + 1e–<\/sup> \u2192 \\(\\frac{1}{2}\\)H2<\/sub>
\nAs the standard reduction potential for H+<\/sup> ions are more it is easily reduced at cathode.
\nAt anode Ch ions are oxidised Cl–<\/sup> \u2192 Cl + e
\n2Cl \u2192 Cl2(g)<\/sub><\/p>\n
![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-17.png\")
![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-18.png\")
![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-19.png\")
<\/p>\n![\"Plus](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2020\/12\/Plus-Two-Chemistry-Previous-Year-Question-Paper-Say-2018-20.png\")
<\/p>\n