{"id":27605,"date":"2020-07-07T16:28:00","date_gmt":"2020-07-07T10:58:00","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=27605"},"modified":"2021-07-02T15:07:07","modified_gmt":"2021-07-02T09:37:07","slug":"2nd-puc-chemistry-previous-year-question-paper-march-2018","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/2nd-puc-chemistry-previous-year-question-paper-march-2018\/","title":{"rendered":"2nd PUC Chemistry Previous Year Question Paper March 2018"},"content":{"rendered":"<p>Students can Download 2nd PUC Chemistry Previous Year Question Paper March 2018, Karnataka <a href=\"https:\/\/kseebsolutions.guru\/2nd-puc-chemistry-model-question-papers-with-answers\/\">2nd PUC Chemistry Model Question Papers with Answers<\/a> helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.<\/p>\n<h2>Karnataka 2nd PUC Chemistry Previous Year Question Paper March 2018<\/h2>\n<p>Time: 3:15 Hours<br \/>\nMax. Marks: 70<\/p>\n<p>Instructions<\/p>\n<ul>\n<li>The question paper has four parts A, B, C, and D. All parts are compulsory.<\/li>\n<li>Write balanced chemical equations and draw labeled diagrams wherever required.<\/li>\n<li>Use Jog tables and simple calculators if necessary (Use of scientific calculators is not allowed).<\/li>\n<\/ul>\n<p style=\"text-align: center;\"><span style=\"color: #0000ff;\">Part &#8211; A<\/span><\/p>\n<p><span style=\"color: #0000ff;\">I. Answer all the following questions: (10 \u00d7 1 = 10)<\/span><\/p>\n<p>Question 1.<br \/>\nState Henry&#8217;s law.<br \/>\nAnswer:<br \/>\nAt constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas present above the surface of the solution.<br \/>\np = K<sub>H<\/sub>. x<br \/>\np: partial pressure of the gas.<br \/>\nx: mole fraction of the gas.<br \/>\nK<sub>H<\/sub>: Henry\u2019s constant.<\/p>\n<p>Question 2.<br \/>\nVan&#8217;t Hoffs factor for a solution is less than one. What is the conclusion drawn from it?<br \/>\nAnswer:<\/p>\n<ul>\n<li>When the solute undergoes dissociation.<\/li>\n<li>When the solute undergoes association.<\/li>\n<li>The solute does not undergo association or dissociation.<\/li>\n<\/ul>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 3.<br \/>\nHow many Faraday of electricity is required to reduce 1 mole of MnO<sub>4<\/sub> ions to Mn<sup>2+<\/sup> ions?<br \/>\nAnswer:<br \/>\n5 Faradays.<\/p>\n<p>Question 4.<br \/>\nIf the unit of the rate constant of a reaction is mol<sup>-1<\/sup> LS<sup>-1<\/sup> then mention its order.<br \/>\nAnswer:<br \/>\nSecond-order.<\/p>\n<p>Question 5.<br \/>\nName a metal refined by Van Arkel method.<br \/>\nAnswer:<br \/>\nZirconium (or) Titanium.<\/p>\n<p>Question 6.<br \/>\nComplete the following equation.<br \/>\nXeF<sub>6<\/sub> + H<sub>2<\/sub>O \u2192 ____ + 2HF<br \/>\nAnswer:<br \/>\nXeOF<sub>4<\/sub>.<\/p>\n<p>Question 7.<br \/>\nWhat is an ambidentate ligand?<br \/>\nAnswer:<br \/>\nLigand which can ligate through 2 different atoms is called ambidentate ligand.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64543\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q7.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q7\" width=\"242\" height=\"125\" \/><\/p>\n<p>Question 8.<br \/>\nName the following reaction.<br \/>\nH<sub>3<\/sub>C &#8211; Br + AgF \u2192 H<sub>3<\/sub>C &#8211; F + AgBr<br \/>\nAnswer:<br \/>\nSwartz reaction<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 9.<br \/>\nEthanal (CH<sub>3<\/sub>CHO) undergoes aldol condensation reaction. Give reason.<br \/>\nAnswer:<br \/>\nEthanal contains \u03b1-hydrogens.<\/p>\n<p>Question 10.<br \/>\nDeficiency of which vitamin causes the disease &#8220;Rickets&#8221;.<br \/>\nAnswer:<br \/>\nVitamin &#8211; D.<\/p>\n<p style=\"text-align: center;\"><span style=\"color: #0000ff;\">Part &#8211; B<\/span><\/p>\n<p><span style=\"color: #0000ff;\">Answer any FIVE questions: (Each question carries two marks) (5 \u00d7 2 = 10)<\/span><\/p>\n<p>Question 11.<br \/>\nWhat is a Frenkel defect? How does it affect the density of the solid?<br \/>\nAnswer:<br \/>\nIt is a type of defect that arises in ionic solids when smaller ion (cation) is dislocated from its normal site to an interstitial site. This defect does not change the density of the solid.<\/p>\n<p>Question 12.<br \/>\nDraw a neat labeled diagram of H<sub>2<\/sub> &#8211; O<sub>2<\/sub> fuel cell. Write the reaction that occurs at the cathode of the cell.<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64545\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q12.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q12\" width=\"295\" height=\"200\" \/><br \/>\nIn this cell, hydrogen and oxygen are bubbled through porous carbon electrodes into concentrated aqueous sodium hydroxide.<br \/>\nHydrogen is fed into the anode compartment where it is oxidized.<br \/>\nThe oxygen is fed into the cathode compartment where it is reduced.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64544\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q12.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q12.1\" width=\"369\" height=\"94\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q12.1.png 369w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q12.1-300x76.png 300w\" sizes=\"(max-width: 369px) 100vw, 369px\" \/><\/p>\n<p>Question 13.<br \/>\nA first-order reaction is found to have a rate constant, K = 5.5 \u00d7 10<sup>-14<\/sup> S<sup>-1<\/sup>. Find the half-life of the reaction.<br \/>\nAnswer:<br \/>\nt\u00bd = 1.26 \u00d7 10<sup>13<\/sup> s<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 14.<br \/>\nGive reason:<br \/>\n(a) Cerium (Ce) exhibits a +4 oxidation state.<br \/>\n(b) Actinoid contraction is greater from element to element than lanthanoid contraction.<br \/>\nAnswer:<br \/>\n(a) Fe<sup>3+<\/sup> is more stable. Fe<sup>3+<\/sup> has a stable half-filled configuration.<br \/>\n(b) A steady decrease in the size of actinoids with an increase in atomic number is known as actinoid contraction.<br \/>\nActinoid contraction is greater from element to element in the series due to poor shielding by 5f electrons compared to 4f electrons.<\/p>\n<p>Question 15.<br \/>\nHow anisole reacts with bromine in ethanoic acid? Write the chemical equation for the reaction.<br \/>\nAnswer:<br \/>\nAnisole undergoes bromination with bromine in ethanoic acid to form ortho-bromoanisole and para-bromoanisole.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64546\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q15.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q15\" width=\"437\" height=\"195\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q15.png 437w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q15-300x134.png 300w\" sizes=\"(max-width: 437px) 100vw, 437px\" \/><\/p>\n<p>Question 16.<br \/>\nExplain the preparation of carboxylic acids from Grignard reagent. Give an equation.<br \/>\nAnswer:<br \/>\nGrignard reagents react with solid carbon dioxide (dry ice) to form a salt of carboxylic acids, which on acidification gives carboxylic acid.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64547\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q16.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q16\" width=\"520\" height=\"37\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q16.png 520w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q16-300x21.png 300w\" sizes=\"(max-width: 520px) 100vw, 520px\" \/><\/p>\n<p>Question 17.<br \/>\nGiven an example each for<br \/>\n(a) Artificial sweetening agents<br \/>\n(b) Narcotic analgesics.<br \/>\nAnswer:<br \/>\n(a) Chemical compounds which give sweet taste without adding calories.<br \/>\nEx: Aspartame, Saccharin, Sucralose, Alitame.<\/p>\n<p>(b) Analgesics are chemicals used to reduce body pain without causing impairment<br \/>\nof consciousness.<br \/>\nEx: Non-norcotic analgesic &#8211; Aspirin<br \/>\nNorcotic analgesic &#8211; Morphine.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 18.<br \/>\nWhat are cationic detergents? Give an example.<br \/>\nAnswer:<br \/>\nCationic detergents are quaternary ammonium salts of amines with acetates, chlorides or bromides as anions.<br \/>\nEx: Cetyltrimethylammonium bromide<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64548\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q18.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q18\" width=\"202\" height=\"124\" \/><br \/>\nThese are used in hair conditioners.<\/p>\n<p style=\"text-align: center;\"><span style=\"color: #0000ff;\">Part &#8211; C<\/span><\/p>\n<p><span style=\"color: #0000ff;\">Answer any FIVE of the following: (Each question carries three marks) (5 \u00d7 3 = 15)<\/span><\/p>\n<p>Question 19.<br \/>\nExplain the process of obtaining &#8220;blister copper&#8221; from &#8220;copper matte&#8221; with equations.<br \/>\nAnswer:<br \/>\nCopper matte is a mixture of a cuprous suiphide and little quantity of ferrous Sulphide.<br \/>\nCopper matte along with some quantity of silica is taken in the converter in which hot air is blown.<br \/>\n(a) Remaining ferrous suiphide oxidizes to ferrous oxide, which in turn combines with silica to form slag ferrous silicate<br \/>\n2FeS + 3O<sub>2<\/sub> \u2192 2FeO + 2SO<sub>2<\/sub><br \/>\nFeO + SiO<sub>2<\/sub> \u2192 FeSiO<sub>3<\/sub><\/p>\n<p>(b) Part of curious suiphide oxidizes to cuprous oxide which combines with remaining cuprous suiphide forming blister copper.<br \/>\n2Cu<sub>2<\/sub>S + 3O<sub>2<\/sub> \u2192 2Cu<sub>2<\/sub>O+ 2SO<sub>2<\/sub><br \/>\n2Cu<sub>2<\/sub>S + Cu<sub>2<\/sub>S \u2192 6Cu + SO<sub>2<\/sub><\/p>\n<p>Question 20.<br \/>\nWrite the equations involved in the manufacture of nitric acid by Ostwald&#8217;s process by maintaining reaction conditions.<br \/>\nAnswer:<br \/>\nStep 1: Catalytic oxidation of ammonia gives nitric oxide.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64550\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q20.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q20\" width=\"322\" height=\"48\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q20.png 322w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q20-300x45.png 300w\" sizes=\"(max-width: 322px) 100vw, 322px\" \/><br \/>\nStep 2: Nitric oxide thus formed combines with oxygen gives NO<sub>2<\/sub><br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64549\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q20.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q20.1\" width=\"173\" height=\"26\" \/><br \/>\nStep 3: Nitrogen dioxide so formed dissolves in water to give HNO<sub>3<\/sub><br \/>\nH<sub>2<\/sub>O + 3NO<sub>2<\/sub> \u2192 2HNO<sub>3<\/sub> + NO<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 21.<br \/>\n(a) How is ozonized oxygen prepared in the laboratory? Give an equation.<br \/>\n(b) Give the composition of &#8220;Oleum&#8221;.<br \/>\nAnswer:<br \/>\nWhen slow dry steam of oxygen is passed through a silent electrical discharge conversion of oxygen to ozone takes place. The product is known as ozonized oxygen.<br \/>\n3O<sub>2<\/sub> \u2192 2O<sub>3<\/sub>, \u2206H = +142 kJ mol<sup>-1<\/sup><\/p>\n<p>Question 22.<br \/>\nComplete the following equations:<br \/>\n(a) 2NaOH + Cl<sub>2<\/sub> \u2192 NaCl + ____ + H<sub>2<\/sub>O<br \/>\n(b) Na<sub>2<\/sub>SO<sub>3<\/sub> + 2HCl \u2192 2NaCl + H<sub>2<\/sub>O + ______<br \/>\n(c) Cl<sub>2<\/sub> + 3F<sub>2<\/sub> \\(\\underrightarrow { 573K }\\) _____<br \/>\nAnswer:<br \/>\n(a) 2NaOH + Cl<sub>2<\/sub> \u2192 NaCl + <span style=\"text-decoration: underline;\">NaClO<\/span> + H<sub>2<\/sub>O<br \/>\n(b) Na<sub>2<\/sub>SO<sub>3<\/sub> + 2HCl \u2192 2NaCl + H<sub>2<\/sub>O + <span style=\"text-decoration: underline;\">SO<sub>2<\/sub><\/span><br \/>\n(c) Cl<sub>2<\/sub> + 3F<sub>2<\/sub> \\(\\underrightarrow { 573K }\\) <span style=\"text-decoration: underline;\">2ClF<sub>3<\/sub><\/span><\/p>\n<p>Question 23.<br \/>\nHow is potassium permanganate (KMnO<sub>4<\/sub>) prepared from MnO<sub>2<\/sub>? Write the equations.<br \/>\nAnswer:<br \/>\nPotassium perchlorate<\/p>\n<p>Question 24.<br \/>\n(a) Why 3d-series of elements act as good catalysts?<br \/>\nAnswer:<br \/>\nInterstitial compounds are those which are formed by the transitional element when small atoms like H, C, and N are trapped inside the crystal lattices of metals.<br \/>\nExample: VH<sub>0.5<\/sub><\/p>\n<p>(b) Given reason: Ti<sup>4+<\/sup> salts are colorless whereas Cr<sup>3+<\/sup> salts are colored.<br \/>\nAnswer:<br \/>\nSc<sup>3+<\/sup> ions do not. contain ai\u00ecy unpaired electrons hence d-d transition does not take place.<br \/>\nCr<sup>3+<\/sup> ions contain 3 unpaired electrons, hence d-d transition take place.<br \/>\nTherefore, Cr<sup>3+<\/sup> ions are colored.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 25.<br \/>\nWith the help of the Valence Bond Theory (VBT), explain hybridization, geometry, and magnetic property of [NiCl<sub>4<\/sub>]<sup>2-<\/sup>.<br \/>\nAnswer:<br \/>\n(i) Orbitals of Ni<sup>2+<\/sup> ion<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64579\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q25.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q25\" width=\"286\" height=\"61\" \/><br \/>\n(ii) In Ni<sup>2+<\/sup> ion sp<sup>3<\/sup> hybridization takes place sp<sup>3<\/sup> hybrid orbitals of Ni<sup>2+<\/sup><br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64551\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q25.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q25.1\" width=\"287\" height=\"61\" \/><br \/>\n(iii) 4 pairs of electrons one from each, occupy the four hybrid orbitals. The complex has tetrahedral geometry and paramagnetic because of two unpaired electrons.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64552\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q25.2.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q25.2\" width=\"433\" height=\"69\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q25.2.png 433w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q25.2-300x48.png 300w\" sizes=\"(max-width: 433px) 100vw, 433px\" \/><br \/>\nFor [Ni(Cl)<sub>4<\/sub>]<sup>2-<\/sup> Complex:<\/p>\n<ul>\n<li>Type of hybridization: sp<sup>3<\/sup><\/li>\n<li>Geometry: Tetrahedral<\/li>\n<li>Magnetic property: Paramagnetic.<\/li>\n<\/ul>\n<p>Question 26.<br \/>\n(a) Write the IUPAC name of [Co(NH<sub>3<\/sub>)<sub>4<\/sub>(H<sub>2<\/sub>O)Cl]Cl<sub>2<\/sub>.<br \/>\nAnswer:<br \/>\nTetraammineaquachloridocobalt(III) chloride<\/p>\n<p>(b) Explain linkage isomerism with example.<br \/>\nAnswer:<br \/>\nTwo or more co-ordination compounds have the same molecular formula but differ in the mode of attachment of the ambident ligand to the central metal ion.<br \/>\nEx: [Co(NH<sub>3<\/sub>)<sub>5<\/sub>(NO<sub>2<\/sub>)]Cl<sub>2<\/sub><br \/>\nPentaamminenitrito-N-cobalt(III) chloride<br \/>\nEx: [Co(NH<sub>3<\/sub>)<sub>5<\/sub>(ONO)]Cl<sub>2<\/sub><br \/>\nPentaamminenitrito-O-cobalt(III) chloride<\/p>\n<p style=\"text-align: center;\"><span style=\"color: #0000ff;\">Part &#8211; D<\/span><\/p>\n<p><span style=\"color: #0000ff;\">Answer any three of the following: (Each question carries five marks) (3 \u00d7 5 = 15)<\/span><\/p>\n<p>Question 27.<br \/>\n(a) Calculate packing efficiency in a simple cubic lattice.<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64581\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q27.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q27\" width=\"238\" height=\"261\" \/><br \/>\nIn simple cubic lattice, the atoms are located only on the corners of the cube.<br \/>\nThe atoms touch each other along the edge.<br \/>\nThe edge length of the cube is \u2018a\u2019. and radius or each atom is r.<br \/>\na = 2r<br \/>\nThe volume of the unit cell is = a<sup>3<\/sup> = (2r)<sup>3<\/sup> = 8r<sup>3<\/sup><br \/>\nSimple cubic mut cells contain only one atom.<br \/>\nThe volume of the one atom = \\(\\frac{4}{3} \\pi r^{3}\\)<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64580\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q27.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q27.1\" width=\"457\" height=\"187\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q27.1.png 457w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q27.1-300x123.png 300w\" sizes=\"(max-width: 457px) 100vw, 457px\" \/><\/p>\n<p>(b) An element having an atomic mass 107.9 u has FCC lattice. The edge length of its unit cell is 408.6 pm. Calculate the density of the unit cell. [Given, N<sub>A<\/sub> = 6.022 \u00d7 10<sup>23 <\/sup>mol<sup>-1<\/sup>].<br \/>\nAnswer:<br \/>\n6.242 g cm<sup>-3<\/sup><\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 28.<br \/>\n(a) The boiling point of benzene is 353.23K. When 1.80 g of a non-volatile, non-ionizable solute was dissolved in 90g of benzene, the boiling point raised to 354.11 K. Calculate the molar mass of the solute. [Kb for benzene = 2.53K Kg mol<sup>-1<\/sup>].<br \/>\nAnswer:<br \/>\nThe boiling point of solution (T) = 354.11 K.<br \/>\nThe boiling point of the solvent (T\u00b0) = 353.23 K.<br \/>\nElevation in boiling point. (\u2206T<sub>b<\/sub>) = T &#8211; T\u00b0 = 354.11 &#8211; 353.23 = 0.88 K.<br \/>\nMass of solute = W<sub>2<\/sub> = 1.80 g<br \/>\nMass of solvent = W<sub>1<\/sub> = 90 g<br \/>\nK<sub>b<\/sub> = 2.53 K.kg mol<sup>-1<\/sup><br \/>\nMolar mass of solute = M<sub>2<\/sub> = ?<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64582\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q28a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q28(a)\" width=\"313\" height=\"153\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q28a.png 313w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q28a-300x147.png 300w\" sizes=\"(max-width: 313px) 100vw, 313px\" \/><\/p>\n<p>(b) Define:<\/p>\n<ol>\n<li>Molality of a solution.<\/li>\n<li>Isotonic solutions.<\/li>\n<\/ol>\n<p>Answer:<\/p>\n<ol>\n<li>Molality is defined as the number of the solute present in one kilogram of solvent.<\/li>\n<li>Two solutions having the same osmotic pressure at a given temperature are called isotonic solutions.<br \/>\nExample: Blood cells are isotonic with 0.9 (m\/v) sodium chloride solution (saline).<\/li>\n<\/ol>\n<p>Question 29.<br \/>\n(a) Calculate e.m.f of the cell for the reaction<br \/>\nMg(s) + Cu<sup>2+<\/sup> (0.0001 M) \u2192 Mg<sup>2+<\/sup> (0.001 M) + Cu(S)<br \/>\nGiven that: \\(\\mathbf{E}_{\\mathrm{Mg}^{2+}}^{0}\\) = -2.37 V, \\(\\mathbf{E}_{\\mathrm{Cu}^{2+} \/ \\mathrm{C}}^{\\mathbf{0}}\\) = +0.34V<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64583\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q29a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q29(a)\" width=\"301\" height=\"191\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q29a.png 301w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q29a-300x190.png 300w\" sizes=\"(max-width: 301px) 100vw, 301px\" \/><\/p>\n<p>(b) (i) State Kohlrausch law.<br \/>\nAnswer:<br \/>\nLimiting the molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte.<br \/>\nIf the molar conductivity of cation is denoted by \\(\\lambda_{+}^{0}\\) and that of anion \\(\\lambda_{-}^{0}\\)<br \/>\n\\(\\wedge_{m}^{\\circ}=v_{+} \\lambda_{+}^{0}+v_{-} \\lambda_{-}^{0}\\)<br \/>\nWhere v<sub>+<\/sub> and v<sub>&#8211;<\/sub> are the number of cations and anions per formula unit of an electrolyte.<\/p>\n<p>(ii) What is meant by limiting molar conductance?<br \/>\nAnswer:<br \/>\nMolar conductivity of an electrolyte solution at infinite dilution (when concentration approaches zero) is called limiting molar conductivity.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 30.<br \/>\n(a) Derive an integrated rate for the first-order reaction.<br \/>\nAnswer:<br \/>\nConsider a zero-order reaction.<br \/>\nR \u2192 P<br \/>\n\\(\\frac{-d[R]}{d t}\\) = k[R]<sup>1<\/sup><br \/>\nwhere k is velocity constant of n first order reaction.<br \/>\n\\(\\frac{-d[R]}{d t}\\) = -k.dt<br \/>\nIntegrating the equation<br \/>\n\u222b\\(\\frac{-d[R]}{d t}\\) = -\u222bk.dt<br \/>\nln[R] = -kt + I &#8230;&#8230;. (1)<br \/>\nI is constant of integration<br \/>\nWhen t = 0, [R] = [R]<sub>0<\/sub> where [R]<sub>0<\/sub> is initial concentration of the reactant.<br \/>\nln[R]<sub>0<\/sub> = -k \u00d7 0 + 1<br \/>\nI = ln[R]<sub>0<\/sub><br \/>\nSubstituting I value in equation (1)<br \/>\nln[R] = -kt + ln[R]<sub>0<\/sub><br \/>\nkt = ln[R]<sub>0<\/sub> &#8211; ln[R]<br \/>\n\\(k=\\frac{2.303}{t} \\log \\frac{[R]_{0}}{[R]}\\)<\/p>\n<p>(b) Draw a graph of potential energy V\/S reaction co-ordinates showing the effect of catalyst on activation energy (E<sub>a<\/sub>) of a reaction.<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64584\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q30b.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q30(b)\" width=\"349\" height=\"216\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q30b.png 349w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q30b-300x186.png 300w\" sizes=\"(max-width: 349px) 100vw, 349px\" \/><br \/>\nCatalyst provides an alternate pathway by reducing the activation energy and lowering the energy barrier. More molecules enter the threshold energy state leading to chemical reaction and hence increases the rate.<\/p>\n<p>Question 31.<br \/>\n(a) Write any two differences between lyophilic and lyophobic colloids.<br \/>\nAnswer:<br \/>\nLyophilic sols (Colloids)<\/p>\n<ul>\n<li>Colloidal particles have an affinity for dispersion medium.<\/li>\n<li>These are very stable.<\/li>\n<li>These are reversible in nature.<\/li>\n<li>Viscosity is higher than that of the dispersion medium.<\/li>\n<\/ul>\n<p>Lyophobic sols (Colloids)<\/p>\n<ul>\n<li>Colloidal particles do not have an affinity for dispersion medium.<\/li>\n<li>These are unstable.<\/li>\n<li>These are irreversible in nature.<\/li>\n<li>Viscosity is the same as that of the dispersion medium.<\/li>\n<\/ul>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>(b) What is heterogeneous catalysis? Give an example.<br \/>\nAnswer:<br \/>\nA catalytic process in which the reactants and the catalyst are in different phases is known as heterogeneous catalysis.<br \/>\nExample (1): Oxidation of sulphur dioxide to sulphur trioxide in presence of platinum catalyst.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64587\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q31b.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q31(b)\" width=\"265\" height=\"39\" \/><br \/>\nExample (2): Combination of hydrogen and nitrogen to form ammonia.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64585\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q31b.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q31(b).1\" width=\"254\" height=\"38\" \/><br \/>\nExample (3): Hydrogenation of vegetable oil<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64586\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q31b.2.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q31(b).2\" width=\"407\" height=\"37\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q31b.2.png 407w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q31b.2-300x27.png 300w\" sizes=\"(max-width: 407px) 100vw, 407px\" \/><\/p>\n<p>(c) Give an expression for Freundlich adsorption isotherm.<br \/>\nAnswer:<br \/>\n\\(\\frac{x}{\\mathrm{m}}=\\mathrm{K} \\cdot p^{1 \/ n}\\)<br \/>\nx is mass of the gas adsorbed.<br \/>\nm is mass of the adsorbent.<br \/>\np is pressure.<br \/>\nK<sub>1<\/sub> and n are constants.<\/p>\n<p><span style=\"color: #0000ff;\">Answer any four of the following. Each question carries five marks: (4 \u00d7 5 = 20)<\/span><\/p>\n<p>Question 32.<br \/>\n(a) Write the equations for the steps in the SN<sub>1<\/sub> mechanism of the conversion of tert-butyl bromide into tert-butyl alcohol.<br \/>\nAnswer:<br \/>\nThe reaction between tert-butyl bromide and hydroxide ion gives tert-butyl alcohol. The rate of reaction depends only on the concentration of tert-butyl bromide. Hence it is a nucleophilic first order substitution reaction.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64590\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q32(a)\" width=\"365\" height=\"107\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.png 365w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a-300x88.png 300w\" sizes=\"(max-width: 365px) 100vw, 365px\" \/><br \/>\nMechanism:<br \/>\nStep 1: Polarised C \u2014 Br undergoes cleavage to produce planar carbocation.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64588\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q32(a).1\" width=\"334\" height=\"111\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.1.png 334w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.1-300x100.png 300w\" sizes=\"(max-width: 334px) 100vw, 334px\" \/><br \/>\nStep 2: The carbocation is then attacked by a nucleophile (OH<sup>&#8211;<\/sup>) on either side to form tert-butyl alcohol.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64589\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.2.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q32(a).2\" width=\"326\" height=\"108\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.2.png 326w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32a.2-300x99.png 300w\" sizes=\"(max-width: 326px) 100vw, 326px\" \/><\/p>\n<p>(b) Explain the Fitting reaction.<br \/>\nAnswer:<br \/>\nwhen aryl halide treated with sodium in ether medium two aryl groups join together to form biphenyl.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64591\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32b.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q32(b)\" width=\"402\" height=\"179\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32b.png 402w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q32b-300x134.png 300w\" sizes=\"(max-width: 402px) 100vw, 402px\" \/><\/p>\n<p>(c) Name the reagent used in the dehydrohalogenation of haloalkanes.<br \/>\nAnswer:<br \/>\nAlcoholic KOH.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 33.<br \/>\n(a) Write the mechanism of acid-catalyzed dehydration of ethanol to ethene.<br \/>\nAnswer:<br \/>\nStep 1: Formation of protonated alcohol<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64594\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q33(a)\" width=\"342\" height=\"92\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a.png 342w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a-300x81.png 300w\" sizes=\"(max-width: 342px) 100vw, 342px\" \/><br \/>\nStep 2: Formation of carbocation<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64592\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a.1.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q33(a).1\" width=\"334\" height=\"101\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a.1.png 334w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a.1-300x91.png 300w\" sizes=\"(max-width: 334px) 100vw, 334px\" \/><br \/>\nStep 3: Formation of ethene by the elimination of a proton<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64593\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q33a.2.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q33(a).2\" width=\"249\" height=\"110\" \/><\/p>\n<p>(b) Between phenol and alcohol which is more acidic? Why?<br \/>\nAnswer:<br \/>\nPhenols are more acidic than alcohols. This is because the phenoxide ion formed from the ionization of phenol is stabilized by resonance.<\/p>\n<p>Question 34.<br \/>\n(a) Explain Rosenmund reduction with the equation.<br \/>\nAnswer:<br \/>\nWhen benzoyl chloride (acid chloride) is hydrogenated with catalyst palladium on barium sulphate, benzaldehyde is obtained.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64595\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q34a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q34(a)\" width=\"343\" height=\"144\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q34a.png 343w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q34a-300x126.png 300w\" sizes=\"(max-width: 343px) 100vw, 343px\" \/><\/p>\n<p>(b) How does propanone (CH<sub>3<\/sub>COCH<sub>3<\/sub>) react with hydrazine? Give an equation.<br \/>\nAnswer:<br \/>\nPropanone undergoes a nucleophilic addition reaction with hydrazine forming addition product Hydrazone.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64596\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q34b.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q34(b)\" width=\"411\" height=\"69\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q34b.png 411w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q34b-300x50.png 300w\" sizes=\"(max-width: 411px) 100vw, 411px\" \/><\/p>\n<p>(c) Name an oxidising agent used in the Etard&#8217;s reaction.<br \/>\nAnswer:<br \/>\nChromyl Chloride (CrO<sub>2<\/sub>Cl<sub>2<\/sub>)<\/p>\n<p>Question 35.<br \/>\n(a) Explain carbyl amine reaction with the equation.<br \/>\nAnswer:<br \/>\nPrimary amines on heating with chloroform and alcoholic KOH form carbylamines.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64597\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q35a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q35(a)\" width=\"380\" height=\"43\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q35a.png 380w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q35a-300x34.png 300w\" sizes=\"(max-width: 380px) 100vw, 380px\" \/><\/p>\n<p>(b) How does nitrobenzene is reduced to aniline? Give an equation.<br \/>\nAnswer:<br \/>\nNitro compounds are reduced to amines by pacing hydrogen ga in the presence of finely divided nickel, palladium, or platinum catalyst.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64598\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q35b.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q35(b)\" width=\"291\" height=\"77\" \/><\/p>\n<p>(c) Write the IUPAC name of<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64599\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q35c.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q35(c)\" width=\"116\" height=\"76\" \/><br \/>\nAnswer:<br \/>\nN, N &#8211; Dimethylbenzanamine<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>Question 36.<br \/>\n(a) Write the Haworth structure of &#8220;Lactose&#8221;.<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64600\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q36a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q36(a)\" width=\"414\" height=\"147\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q36a.png 414w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q36a-300x107.png 300w\" sizes=\"(max-width: 414px) 100vw, 414px\" \/><\/p>\n<p>(b) (i) What are non-essential amino acids?<br \/>\nAnswer:<br \/>\nAmino acids that are synthesized in the body are known as non-essential amino acids.<br \/>\nExample: Glycine, Alanine.<br \/>\nAmino acids that are not synthesized in the body and must be supplied through the diet are known as essential amino acids.<br \/>\nExample: Lysine, Histidine.<\/p>\n<p>(ii) Write the Zwitterionic structure of &#8220;glycine&#8221;.<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64601\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q36bii.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q36(b)(ii)\" width=\"337\" height=\"233\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q36bii.png 337w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q36bii-300x207.png 300w\" sizes=\"(max-width: 337px) 100vw, 337px\" \/><\/p>\n<p>(c) Name the nitrogenous base present in RNA but not in DNA.<br \/>\nAnswer:<br \/>\nUracil<\/p>\n<p>Question 37.<br \/>\n(a) Explain the preparation of Nylon-6, 6 with the equation.<br \/>\nAnswer:<br \/>\nIt is obtained by the condensation polymerization of hexamethylene diamine with adipic acid under high pressure and at high temperatures.<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64602\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q37a.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q37(a)\" width=\"638\" height=\"64\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q37a.png 638w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q37a-300x30.png 300w\" sizes=\"(max-width: 638px) 100vw, 638px\" \/><\/p>\n<p>(b) What are thermoplastic polymers? Give an example.<br \/>\nAnswer:<br \/>\nThermoplastic polymers: These are linear chain polymers in which intermolecular forces are intermediate between elastomers and fibers. These are the polymers softened on heating and harden on cooling.<br \/>\nEx: Polythene, PVC, Polystyrene.<\/p>\n<p><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2019\/11\/KSEEB-Solutions.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018\" width=\"172\" height=\"16\" \/><\/p>\n<p>(c) Write the structure of isoprene (2-methyl-1, 3-butadiene).<br \/>\nAnswer:<br \/>\n<img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-64603\" src=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q37c.png\" alt=\"2nd PUC Chemistry Previous Year Question Paper March 2018 Q37(c)\" width=\"416\" height=\"271\" srcset=\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q37c.png 416w, https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2020\/07\/2nd-PUC-Chemistry-Previous-Year-Question-Paper-March-2018-Q37c-300x195.png 300w\" sizes=\"(max-width: 416px) 100vw, 416px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Students can Download 2nd PUC Chemistry Previous Year Question Paper March 2018, Karnataka 2nd PUC Chemistry Model Question Papers with Answers helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations. Karnataka 2nd PUC Chemistry Previous Year Question Paper March 2018 Time: 3:15 Hours Max. Marks: 70 Instructions &hellip;<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/27605"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=27605"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/27605\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=27605"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=27605"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=27605"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}