{"id":18294,"date":"2020-01-06T15:33:15","date_gmt":"2020-01-06T10:03:15","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=18294"},"modified":"2021-07-02T15:30:45","modified_gmt":"2021-07-02T10:00:45","slug":"2nd-puc-chemistry-previous-year-question-paper-june-2019","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/2nd-puc-chemistry-previous-year-question-paper-june-2019\/","title":{"rendered":"2nd PUC Chemistry Previous Year Question Paper June 2019"},"content":{"rendered":"

Students can Download 2nd PUC Chemistry Previous Year Question Paper June 2019, Karnataka 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

Karnataka 2nd PUC Chemistry Previous Year Question Paper June 2019<\/h2>\n

Time: 3 Hrs 15 Min
\nMax. Marks: 70<\/p>\n

Part-A<\/span><\/p>\n

I. Answer all the questions each question carries one mark following: (10 \u00d7 1 = 10)<\/span><\/p>\n

1.
\nWrite the unit of molality of a solution?
\nAnswer:
\nmol \/ kg-1<\/sup> or mol \/ kg<\/p>\n

2.
\nAt a given temperature, oxygen gas is more soluble in water than Nitrogen gas. Which one of them has higher value of KH?
\nAnswer:
\nN2<\/sub> or Nitrogen<\/p>\n

3.
\nState Faraday\u2019s first law of electrolysis.
\nAnswer:
\nThe amount of substance discharged at any electrode during electrolysis is proportional to the quantity of electricity passed through the electrolyte.<\/p>\n

4.
\nGive an example for pseudo first order reaction.
\nAnswer:
\nInversion of cane sugar OR
\n\"2nd<\/p>\n

\"KSEEB<\/p>\n

5.
\nEnthalpy of physical adsorption is quite low : Give reason.
\nAnswer:
\nBecause it involves weak van der Waals\u2019 forces.<\/p>\n

6.
\nName the method used for concentration of sulphide ores.
\nAnswer:
\nFroth Floatation Method or Process.<\/p>\n

7.
\nAmong Noble gases which one is most abundant in air?
\nAnswer:
\nArgon<\/p>\n

8.
\nName the major organic product formed when 2 – bromopentane is heated with alcoholic potassium hydroxide solution.
\nAnswer:
\nPent – 2 – ene or 2 – Pentene<\/p>\n

9.
\n\"2nd
\nName the above reaction.
\nAnswer:
\nGatterman – Koch reaction.<\/p>\n

10.
\nName the Hormone which regulates blood sugar level.
\nAnswer:
\nInsulin or Glucagon.<\/p>\n

Part-B<\/span><\/p>\n

II. Answer any FIVE questions: (Each question carries two marks) (5 \u00d7 2 = 10)<\/span><\/p>\n

11.
\nWhich type of extrinsic semiconductor is formed when silicon is doped with phosphorus? Mention the major charge carrier in it.
\nAnswer:
\nn – type, Electron (s).<\/p>\n

12.
\nDraw a neat labeled diagram of Standard Hydrogen Electrode (SHE). Write its Half – Cell reaction.
\nAnswer:
\n\"2nd
\nSHE is Symbolically represent as Pt, H2<\/sub>( 1 bar)\/H+<\/sup>(1M)<\/p>\n

\"KSEEB<\/p>\n

13.
\nName any two factors affecting the rate of a reaction.
\nAnswer:<\/p>\n

    \n
  1. Concentration of the reactants<\/li>\n
  2. Temperature of the reactants<\/li>\n
  3. Nature of the reacting substances<\/li>\n<\/ol>\n

    14.
    \n(a) Zr and Hf have almost identical radii : Give reason.
    \nAnswer:
    \nDue to Lanthanoid contraction.<\/p>\n

    (b) Name the gas liberated when Lanthanoids (Ln) react with acids.
    \nAnswer:
    \nHydrogen gas or H2<\/sub> gas<\/p>\n

    15.
    \nHow does phenol react with Cone. HNO3<\/sub>? Give equation.
    \nAnswer:
    \nWhen phenol is heated with concentrated nitric acid, 2,4, 6 – trinitrophenol (picric acid) is formed.
    \n\"2nd<\/p>\n

    16.
    \nExplain Cannizzaro reaction with an example.
    \nAnswer:
    \nAldehydes with no \u03b1 – hydrogen atom when treated with concentrated alkali (NaOH or KOH), undergo self – oxidation and reduction (disproporttionation) to give carboxylic acid salt and alcohol. This is called Cannizzaro\u2019s reaction.
    \n2HCHO + Conc.KOH \u2192 HCOOK + CH3<\/sub>OH<\/p>\n

    17.
    \nWhat is the role of the following chemicals in food?
    \na) Sodiumbenzoate
    \nAnswer:
    \nFood preservative<\/p>\n

    b) Saccharin
    \nAnswer:
    \nArtificial sweetening agent.<\/p>\n

    \"KSEEB<\/p>\n

    18.
    \nWhat is saponification? Write the equation to get sodium stearate by this method.
    \nAnswer:
    \nWhen oil or fat is heated with aqueous NaOH, sodium salts of fatty acids (soaps) are formed.
    \n\"2nd<\/p>\n

    Part-C<\/span><\/p>\n

    III. Answer any FIVE of the following: (Each question carries three marks) (5 \u00d7 3 = 15)<\/span><\/p>\n

    19.
    \nIn the extraction of Aluminium by Hall – Herault process
    \na) Write the neat labeled diagram of electrolytic cell.
    \nAnswer:
    \n\"2nd<\/p>\n

    b) Give the equation of overall cell reaction.
    \nAnswer:
    \n2Al2<\/sub>O3<\/sub> + 3C \u2192 4Al + 3CO2<\/sub><\/p>\n

    c)
    \nWhat is the role of cryolite?
    \nAnswer:
    \nIt lowers the melting point of the electrolyte (mix) and brings conductivity.<\/p>\n

    \"KSEEB<\/p>\n

    20.
    \nIn the manufacture of ammonia by Haber’s process. Write the flow chart and chemical equations with optimum conditions.
    \nAnswer:
    \nAmmonia is manufactured by the direct combination of nitrogen and hydrogen in the ratio 1:3 by volume.
    \nReaction : N2<\/sub> + 3H2(g)<\/sub> \u21cc N2<\/sub>NH3(g)<\/sub> ;
    \n\u0394H = -46 kJ\/mol
    \nAccording to Le-Chatelier’s principle, high yield of Ammonia is obtained under the following favourable conditions.
    \n(a) High pressure of 200atm
    \n(b) Temperature of ~ 700K
    \n(c) Use of Iron oxide as Catalyst in presence of small amounts of K2<\/sub>O and Al2<\/sub>O3<\/sub> as promoters.
    \n\"2nd
    \nProcedure:
    \nStep – 1 : Dry N2<\/sub> and H2<\/sub> in the ratio 1 : 3 compressed at 200 atm in compresser.
    \nStep – 2 : Compressed gas passed through catalytical chamber, in presence of Fe, catalytical promoter Mo and 700 K forms ammonia.
    \nStep – 3 : The ammonia formed is cooled in coolent below 239 K.
    \nStep – 4 : The unreacted nitrogen and hydrogen are recirculated to compressor using pump. The above step repeated to get maximum yield.<\/p>\n

    21.
    \nComplete the following equations :
    \na) 4AI + 3O2<\/sub> \u2192
    \nb) PbS(S)<\/sub> + 4O3(g)<\/sub> \u2192
    \nc) C + 2H2<\/sub>SO4<\/sub> \u2192
    \n(Conc.)
    \nAnswer:
    \na) 2Al2<\/sub>O3<\/sub>
    \nb) PbSO4<\/sub> + 4O2<\/sub>
    \nc) 2H2<\/sub>O + CO2<\/sub> + 2SO2<\/sub><\/p>\n

    22.
    \na) Give any two reasons for anomalous behavior of Fluorine.
    \nAnswer:<\/p>\n

      \n
    1. Ionization enthalpy, electro negativity and electrode potentials are all higher for fluorine than others.<\/li>\n
    2. Hydrogen fluoride is a liquid due to strong hydrogen bonding. Other hydrogen halides are gases.<\/li>\n<\/ol>\n

      b) Write the structure of perchloric acid (HClO4<\/sub>).
      \n\"2nd<\/p>\n

      \"KSEEB<\/p>\n

      23.
      \na) Calculate the spin only magnetic moment of Ti3+<\/sup> ion (Atomic number of Ti = 22).
      \nAnswer:
      \n\u00b5 = \\(\\sqrt{n(n+2)}\\) n = 1
      \n\u00b5 = \\(\\sqrt{1(1+2)}\\)
      \n\u00b5 = \\(\\sqrt{3}\\) =1.7 BM<\/p>\n

      b) Cu2+<\/sup> salt solutions are coloured : Give reason.
      \nAnswer:
      \nDue to the presence of unpaired electron or due to d – d transition of electrons.<\/p>\n

      24.
      \nWrite the balanced equations involved in the preparation of potassium dichromate (K2<\/sub>Cr2<\/sub>O7<\/sub>) from chromite ore.
      \nAnswer:
      \n4FeCr2<\/sub>O4<\/sub> + 8 Na2<\/sub>CO3<\/sub> + 7O2<\/sub> \u2192 8Na2<\/sub>CrO4<\/sub> +2Fe2<\/sub>O4<\/sub> + 2Fe2<\/sub>O3<\/sub> + 8CO2<\/sub>
      \nOR
      \n2Na2<\/sub>CrO4<\/sub> + 2H+<\/sup> \u2192 Na2<\/sub>Cr2<\/sub>O7<\/sub> + 2Na+<\/sup> + H2<\/sub>O
      \n2Na2<\/sub>CrO4<\/sub> + H2<\/sub>SO4<\/sub> \u2192 Na2<\/sub>Cr2<\/sub>O7<\/sub> + Na2<\/sub>SO4<\/sub> + H2<\/sub>O
      \nNa2<\/sub>Cr2<\/sub>O7<\/sub> + 2KCl \u2192 K2<\/sub>Cr2<\/sub>O7<\/sub> + 2NaCl.<\/p>\n

      25.
      \nExplain the hybridization, geometry and magnetic property of [Co(NH3<\/sub>)6<\/sub>]3+<\/sup> ion on the basis of Valance Bond Theory (VBT), (Atomic number of Co = 27].
      \nAnswer:
      \n\"2nd
      \nGeometry of [Co (NH3<\/sub>)6<\/sub>]3+<\/sup><\/sub>\u00a0is Octahedral
      \nMagnetic property: Diamagnetic<\/p>\n

      26.
      \na) For a given complex [Co(NH3<\/sub>)5<\/sub>NO2<\/sub>]Cl2<\/sub>. Write its IUPAC name and Linkage isomer.
      \nAnswer:
      \nPentaamminenitrito – N – Cobalt (III) chloride.
      \n[CO(NH3<\/sub>)5<\/sub> (ONO)]Cl2<\/sub><\/p>\n

      b) Which set of d – orbitals of a metal atom \/ ion experience more repulsion in octahedral field created by the ligands?
      \nAnswer:
      \ndx2<\/sup> – y2<\/sup> and dz2<\/sup> orbitals.<\/p>\n

      \"KSEEB<\/p>\n

      Part-D<\/span><\/p>\n

      IV. Answer any three of the following: (Each question carries fire marks) (3 \u00d7 5= 15)<\/span><\/p>\n

      27.
      \n(a) Calculate the packing efficiency in Face Centred Cubic (FCC) lattice.
      \nAnswer:
      \nThe number of atoms per unit cell in fCC structures is \u20184\u2019
      \nEach atom is considered as one sphere.
      \nSo the volume of 4 atoms
      \n\"2nd
      \n(4 sphere) = 4 \u00d7 \\(\\frac { 3 }{ 4 }\\) \u03c0r3<\/sup> = \\(\\frac { 16 }{ 3 }\\) \u03c0r3<\/sup>
      \nEdge length a = 2\\(\\sqrt{2} r\\)
      \nThe volume of the cubic unit cell = a3<\/sup> = \\((2 \\sqrt{2} r)^{3}\\)
      \n\"2nd<\/p>\n

      b) If a metal with atomic mass 209 crystallizes in a simple cubic lattice what is the edge length of its unit cell. (Given d = 91.5 kg m-3<\/sup>). 2
      \nAnswer:
      \n\"2nd<\/p>\n

      (c) Write any two differences between Frenkel and Schottkydefects.
      \nAnswer:
      \n\"2nd<\/p>\n

      \"KSEEB<\/p>\n

      28.
      \n(a) On dissolving 2.34g of non – electrolyte solute in 40g of benzene, the boiling point of solution was higher than benzene by 0.81 K. Kb value for benzene in 2.53 K kgmol-1<\/sup>. Calculate the molar mass of solute. [Molar mass of benzene is 78 gmol-1<\/sup>]
      \nAnswer:
      \n\"2nd
      \nKb<\/sub> = 2.53 K kg mol-1<\/sup> w1<\/sub> = 40g,
      \nw2<\/sub> = 2.34g, M2<\/sub> = ?, \u0394Tb<\/sub> = 0.81 K
      \n\"2nd<\/p>\n

      (b)
      \ni) State Henry\u2019s law.
      \nAnswer:
      \nThe partial pressure of the gas in vapor phase is proportional to the mole fraction of the gas in the solution.<\/p>\n

      ii) How solubility of\u00a0 a gas in liquid changes with increase in temperature?
      \nAnswer:
      \nDecreases.<\/p>\n

      29.
      \n(a) For a given data : E0<\/sup>Mg2+<\/sup> \/Mg<\/sub> = -2.37V E0<\/sup>Cu2+<\/sup>\/Cu<\/sub> = +0.34V
      \nCalculate the emf of the cell in which the following reaction takes place.
      \n\"2nd
      \nAnswer:
      \nE0<\/sup>cell<\/sub> = E0<\/sup>Cu2+<\/sup>\/Cu<\/sub> – E0<\/sup>Mg2+<\/sup> \/Mg<\/sub>
      \n= 0.34 – (-2.37) = 2.71V
      \n\"2nd<\/p>\n

      (b) State Kohlrausch law of independent migration of ions.
      \nAnswer:
      \nThe limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte.<\/p>\n

      c) Write the overall cell reaction in mercury cell.
      \nAnswer:
      \nZn(Hg) + HgO (s) \u2192 ZnO(s) + Hg(l)<\/p>\n

      \"KSEEB<\/p>\n

      30.
      \n(a) Derive an integrated rate equation for the rate constant of a first-order reaction.
      \nAnswer:
      \nconsider a first order reaction
      \nR \u2192 p
      \nA\/c to Rate law, Rate = k[R]1<\/sup>
      \n\"2nd
      \nwhere I is the integration constant
      \nwhen t = 0, [R] = [R]0<\/sub>
      \nIn [R]0<\/sub> = -k \u00d7 o + I
      \nI = In [R]0<\/sub>
      \nwhere [R]0<\/sub> is the initial con of the reactant ‘R’ substituting the value of I in equation (1)
      \nwe get In [R]0<\/sub> = – kt + [R]0<\/sub>
      \nkt = In [R]0<\/sub> – In [R]
      \n\"2nd<\/p>\n

      (b) The rate constant of a reaction is doubled when the temperature increased from 400K to 410 K. Calculate the activation energy (Ea) [R = 8.314 JK-1<\/sup>mol-1<\/sup>]
      \nAnswer:
      \n\"2nd<\/p>\n

      \"KSEEB<\/p>\n

      31.
      \n(a) How is Gold – Sol prepared by Bredig\u2019s – arc method?
      \nAnswer:
      \nThis process involves dispersion as well as condensation. It is used to prepare sols of metals such as gold, silver, platinum etc.<\/p>\n

        \n
      • In this method, electric arc is struck between electrodes of the metal immersed in the dispersion medium contianing a little alkali.<\/li>\n
      • The intense heat produced vaporizes the metal which then condenses to form particles of colloidal size. The colloidal particles formed adsorb charges from the solution and get stabilized.<\/li>\n<\/ul>\n

        \"2nd<\/p>\n

        (b) What is Homogeneous catalysis? Give an example.
        \nAnswer:
        \nA reaction in which all the reactants and the catalyst are in the same phase is called homogeneous catalysis.
        \n\"2nd<\/p>\n

        (c) How does entropy change ( \u0394 S) for adsorption?
        \nAnswer:
        \nEntropy decreases OR \u0394 S = -ve<\/p>\n

        \"KSEEB<\/p>\n

        V. Answer any four of the following. Each question carries five marks: (4 \u00d7 5 = 20)<\/span><\/p>\n

        32.
        \n(a) Write the equations for the steps involved in SN1<\/sup> mechanism for the conversion of tert – butyl bromide to tert – butyl alcohol.
        \nAnswer:
        \nSN1<\/sup> mechanism involves two steps
        \nStep -1: Formation of carbocation:
        \n\"2nd<\/p>\n

        Step – 2: Attack of nucleophile on carbocation
        \n\"2nd<\/p>\n

        (b) Explain Friedel – Crafts alkylation for chlorobenzene. Give equation.
        \nAnswer:
        \nAn alkyl group can be added to a benzene molecule by an electrophile aromatic substitution reaction called the friedel – crafts alkylation reaction.
        \n\"2nd<\/p>\n

        (c) What is recemic mixture?
        \nAnswer:
        \nEquimolar mixture of dextrorotatory and laevorotatory isomers of the same compound is called racemic mixture.<\/p>\n

        33.
        \n(a) Explain the mechanism of acid catalysed dehydration of ethanol to ethene.
        \nAnswer:
        \n\"2nd
        \n\"2nd<\/p>\n

        b) An organic compound with molecular formula C6<\/sub>H6<\/sub>O gives white precipitate with bromine water. Identify the functional group in the organic compound and write the chemical equation for the reaction.
        \nAnswer:
        \n\"2nd<\/p>\n

        (c) Write general equation for preparation of ether by Williamson synthesis.
        \nAnswer:
        \nR – X + R1<\/sup>ONa \u2192 R – O – R1<\/sup> + NaX<\/p>\n

        (d) Among alcohols and phenols which one is more acidic?
        \nAnswer:
        \nPhenol<\/p>\n

        \"KSEEB<\/p>\n

        34.
        \n(a) Complee the following equations
        \n\"2nd
        \nAnswer:
        \nRCOOH<\/p>\n

        \"2nd
        \nAnswer:
        \nCH4<\/sub><\/p>\n

        (b) Explain Aldol condensation reaction for acetaldehyde. Write equation.
        \nAnswer:
        \nA \u03b2 – hydroxy aldehyde is known as aldol.
        \nIt is produced by the condesation reaction of two molecules of the same or one molecule each of two different aldehydes in the presence of a base.
        \n\"2nd<\/p>\n

        (c) What is Formalin solution?
        \nAnswer:
        \n40% aqueous solution of formaldehyde.<\/p>\n

        35.
        \n(a)How does Primary amine undergo carbyl amine reaction? Give chemical equation.
        \nAnswer:
        \nPrimary amines when heated with chloroform and alcoholic KoH give isoyanides having very unpleasant smell. The reaction is called as Carbylamine reaction.
        \n\"2nd<\/p>\n

        (b) How aniline is prepared by Hoffmann bromamide degradation reaction? Give equation.
        \nAnswer:
        \nBenzamide is treated with bromine in aqueoues or ethanolic solution of sodium hydroxide to form aniline.
        \nC6<\/sub>H5<\/sub>CONH2<\/sub> + Br2<\/sub>+ 4 NaOH \u2192
        \nC6<\/sub>H5<\/sub> NH2<\/sub> + Na2<\/sub>CO3<\/sub> + 2NaBr + 2H2<\/sub>O
        \nOR
        \n\"2nd<\/p>\n

        (c) Write the genera! formula of diazonium salt
        \nAnswer:
        \nRN2<\/sub>+<\/sup>X–<\/sup> R= Aryl group OR ArN\/X<\/p>\n

        \"KSEEB<\/p>\n

        36.
        \n(a)Write the Haworth structure of maltose.
        \nAnswer:
        \n\"2nd<\/p>\n

        (b) What are hormones? Give one biological function of insulin. 2
        \nAnswer:
        \nHormones are the biochemical messengers secreted by endocrine (ductless) glands.
        \nInsulin regulates the blood sugar leveL<\/p>\n

        (c) What are nucleosides? 1
        \nAnswer:
        \nThe compounds containing pentose sugar and nitrogen base are called nucleosides.<\/p>\n

        (d) i) Name a naturally occuring oc-amino acid which is optically inactive.
        \nAnswer:
        \nGlycine<\/p>\n

        ii) How many peptide bonds are present in a tripeptide?
        \nAnswer:
        \nTwo peptide bonds are formed.<\/p>\n

        (e) Deficiency of which Vitamin causes Night blindness?
        \nAnswer:
        \nVitamin – A<\/p>\n

        37.
        \n(a)What is meant by polymerization? Name the monomer used in the preparation of Polyvinyl Chloride (PVC).
        \nAnswer:
        \nThe process of formation of polymers from respective monomers.
        \nVinyl chloride OR Chloroethene.<\/p>\n

        (b) Write partial structure of the following polymers,
        \ni) Polypropene
        \nAnswer:
        \n\"2nd<\/p>\n

        ii) Teflon
        \n\"2nd<\/p>\n

        iii) Neoprene.
        \n\"2nd<\/p>\n","protected":false},"excerpt":{"rendered":"

        Students can Download 2nd PUC Chemistry Previous Year Question Paper June 2019, 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 June 2019 Time: 3 Hrs 15 Min Max. Marks: …<\/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\/18294"}],"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=18294"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/18294\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=18294"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=18294"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=18294"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}