{"id":18075,"date":"2020-01-06T09:52:09","date_gmt":"2020-01-06T04:22:09","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=18075"},"modified":"2021-07-02T15:31:11","modified_gmt":"2021-07-02T10:01:11","slug":"2nd-puc-chemistry-model-question-paper-4","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/2nd-puc-chemistry-model-question-paper-4\/","title":{"rendered":"2nd PUC Chemistry Model Question Paper 4 with Answers"},"content":{"rendered":"

Students can Download 2nd PUC Chemistry Model Question Paper 4 with Answers, 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 Model Question Paper 4 with Answers<\/h2>\n

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

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

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

Question 1.
\nName the law behind the dissolution of CO2<\/sub> gas in solf under high pressure?
\nAnswer:
\nHenry\u2019s law.<\/p>\n

Question 2.
\nOrnamental gold containig copper is an example for what type of solution ?
\nAnswer:
\nSolid – solid solution.<\/p>\n

Question 3.
\nWhich gas is evolved at cathode during the electrolysis of an aqueous solution of Na Cl?
\nAnswer:
\nChlorine.<\/p>\n

Question 4.
\nWhat happens to the half life period of a first order reaction if the initial concentration of the reactants is increased ?
\nAnswer:
\nHalf-life of a first order reaction is independent of the initial concern trution it remains constant.<\/p>\n

\"KSEEB<\/p>\n

Question 5.
\nOut of physisorption and chemisorption which one has lower enthalpy of edsorption ?
\nAnswer:
\nPhysisorption las lower enthalapy.<\/p>\n

Question 6.
\nGive the composition of copper matte.
\nAnswer:
\nCU2<\/sub>S – Fes<\/p>\n

Question 7.
\nNoble gases are chemically inert give one reason ?
\nAnswer:
\nThe orbitals and of noble gases are completely filled they generally have 8 valence electrons and have stable electronic configuration hence they are chemically inert<\/p>\n

Question 8.
\nWhat is \u201cChirality\u201d?
\nAnswer:
\nChirality is a geometric property of some molecules andions a chiral molecule or ion is non super posable on its mirror image the presence of asymmetric carbon atom is one of several structural featares that induce chirality in organic an dinorganic molecules<\/p>\n

Question 9.
\nComplete the following chemical reaction.
\n\"2nd
\nAnswer:
\n\"2nd<\/p>\n

Question 10.
\nWhich hormone regulates the sugar level in the blood?
\nAnswer:
\nInsulin or glucagon.<\/p>\n

Part – B<\/span><\/p>\n

II. Answer any five of the following questions (5 \u00d7 2 = 10)<\/span><\/p>\n

Question 11.
\nCalculate the no of particles ( atoms) per unit cell in a FCC crystal lattice?
\nAnswer:
\nNo.of atoms per unit cell of FCC = 8 comer atoms \u00d7 \\(\\frac { 1 }{ 8 }\\) atom +6 facecentred atoms \u00d7 \\(\\frac { 1 }{ 2 }\\)
\ni. e.8 \u00d7 \\(\\frac { 1 }{ 8 }\\)+ 6 \u00d7 \\(\\frac { 1 }{ 2 }\\) =1 + 3 = 4<\/p>\n

Question 12.
\nWhat are ferromagnetic substances? give one example.?
\nAnswer:
\nThe substances which are strongly affected by magnetic field are called ferromagnetic substances and the phenomenon is known as ferromagnetism.
\nEx: Iron or Nickel, or Cobalt or CrO2<\/sub> any other.<\/p>\n

\"KSEEB<\/p>\n

Question 13.
\nThe rate contant of a certain first order reaction is 200 S-1<\/sup>. What is its half life period ?
\nAnswer:
\nfor a first order reaction
\n\"2nd<\/p>\n

Question 14.
\nZr and Hf have almost identical radii give reason ?
\nAnswer:
\nIt is due to Lanthanoid contraction.<\/p>\n

Question 15.
\nExplain Kolbe’s reaction ?
\nAnswer:
\nSodium phenate is treated with carbon dioxide and the product on acidification forms salicylic acid. This reaction is called Kolbe\u2019s reaction.<\/p>\n

\"2nd
\nethanal ( acetaldehyde )? name the reaction?
\nAnswer:
\nAldehydes and ketones having at least often hydrogen under go a reaction in the presence of dilute alkali as catalyst to form \u03b2- hydroxy aldehydes (aldol) or \u03b2 -hydroxy ketones (ketol), respectively. This is known as Aldol reaction.
\n\"2nd<\/p>\n

Question 17.
\nWhat is the role of following chemicals in food ?
\ni) Saccharin
\nAnswer:
\nSaccharine is the well known sweetening agent which is more than 550 times sweet as compared to sucrose (or sugar). It is commonly used in the preparation of sweets for diabetic patients. Actually, it is not a carbohydrate. Now better sweetening agents are also available.<\/p>\n

ii) Sodium benzoate
\nAnswer:
\nSodium benzate is a chemical used as a food preservative to stop spoilage of food.<\/p>\n

Question 18.
\nWhat are antifertility drugs? give an example ?
\nAnswer:
\nAnti fertility drugs are those enemical compounds which prevent pregnancy in women. Eg: novethin drone<\/p>\n

\"KSEEB<\/p>\n

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

III. Answer any five of the following questions: each question carries three marks (5 x 3 = 15)<\/span><\/p>\n

Question 19.
\nIn the extraction of aluminium by electrolysis? (3)
\ni) Give the composition of electrolyte used
\nii) Overall cell reaction
\niii) Role’ of cryolite
\nAnswer:
\nRemoves silica impurity as slg calcium silicate.
\nCryolite increases conductivity and reduces melting point of Al2<\/sub>O3<\/sub>.
\nAluminium Extraction
\nCathode : Al3+<\/sup>(melt) + 3e–<\/sup> + al(l)
\nAnode : C(s) + O2-<\/sup>(melt) CO(g) + 2e
\nC(s) + 2O2-<\/sup>(melt) CO2<\/sub>(g) + 2e
\nOverall reaction: 2Al2<\/sub>O3 <\/sub>+ 3C 4Al + 3CO2<\/sub><\/p>\n

Question 20.
\nWrite the balanced chemical equation with condition involved in manufacture of nitric acid by ostwald\u2019s process. (3)
\nAnswer:
\nNitric acid in Ostwald process manufactured by the oxidation of ammonia.
\n\"2nd
\n2NO(g) + O2<\/sub>(g) \u2192 2NO2<\/sub>(g)
\nNitrogen dioxide so formed, dissolves in water to give HNO3<\/sub>.
\n3NO2<\/sub>(g)+H2<\/sub>O (I) \u2192 2HNO3<\/sub>(aq) + NO(g)
\nDilute nitric acid on distillation followed by dehydration using conc. sulphuric acid gives 98% nitric acid.<\/p>\n

Question 21.
\nComplete the following chemical equations
\ni) pbs + 4O3<\/sub> \u2192 pbSO4<\/sub> + _____
\nii) Cu + 2H2<\/sub>SO4<\/sub> \u2192 CuSO4<\/sub> + _____ + 2H2<\/sub>O
\niii) Cl2<\/sub> + 2H2<\/sub>O + SO2<\/sub> \u2192 _____ + 2Hcl
\nAnswer:
\npbs + 4O3<\/sub> \u2192 pbSO4<\/sub> + 4O2<\/sub>
\nCu + 2H2<\/sub>SO4<\/sub> \u2192 CuSO4<\/sub> + SO2<\/sub> + 2H2<\/sub>O
\nCl2<\/sub> + 2H2<\/sub>O + SO2<\/sub> \u2192 H2<\/sub>SO4<\/sub> + 2Hcl<\/p>\n

Question 22.
\na) How is chlorine prepared using KMnO4<\/sub>
\nAnswer:
\nBy the action of HCl on KMnO4<\/sub>.
\n2KMnO4<\/sub>+ 16HCl \u2192 2KCl + 2MnCl2<\/sub> + 8H2<\/sub>O + 5Cl2<\/sub> .<\/p>\n

b) Why is I2 less reactive than Icl ?
\nAnswer:
\nBecause interhalogen compounds are more reactive than halogens the bond between atoms in inter halogens (x – x1<\/sup>) is weaker than the bond in halogens (x – x) hence ICL is more reactive than I2<\/sub><\/p>\n

Question 23.
\na) Calculate the spin only magnetic moment of Fe2+<\/sup>
\nAnswer:
\nFe2+<\/sup> ion has electmic configuration (Ar)4S0<\/sup>3d6<\/sub>
\nit has four supaired electrons \u2234 n = 4
\nspin only magnetic moment \u03bc = \\(\\sqrt{n(n+2)} BM\\)
\n= \\(\\sqrt{4(4+2)} BM\\) = \\(\\sqrt{24} \\mathrm{BM}\\) = 4.9BM<\/p>\n

b) Why Sc3+<\/sup> salts are colourless whereas Cr3+<\/sup> salts are coloured
\nAnswer:
\nThe ions Sc3+<\/sup> have completely empty d- orbitals i e no unpaired electrons are present {[ Ar] 3d0<\/sup>} thus their salts are colourless as d – d transitions are not possible<\/p>\n

\"KSEEB<\/p>\n

Question 24.
\nWrite the balanced equations in the manufacture of K2<\/sub>Cr2<\/sub>O7<\/sub> from cromite ore?
\nAnswer:
\nManufacture of K2<\/sub>Cr2<\/sub>O7<\/sub> from chromite ore involves the following steps
\nStep -1: Conversion of chromite ore into sodium chromate:
\nChromite ore is heated with Na2<\/sub>CO3<\/sub> in the presence of excess of air to form sodium chromate
\n4FeOCr2<\/sub>O3<\/sub> + 8Na2<\/sub>CO3<\/sub> + 7O2 <\/sub>\u2192 8Na2<\/sub>CrO4<\/sub> + 2Fe2<\/sub>O3<\/sub> + 8CO2<\/sub><\/p>\n

Step – 2 : Conversion of sodium chromate into sodium di chromate.
\nThe yellow solution of sodium chromate is filtered and acidified with H2<\/sub>SO4<\/sub> to give a mix-ture of Na2<\/sub> Cr2<\/sub>O7<\/sub> and sodium sulphate
\n2Na2<\/sub>CrO4<\/sub> + H2<\/sub>SO4<\/sub> \u2192 Na2<\/sub> Cr2<\/sub>O7<\/sub> + Na2<\/sub>SO4<\/sub>+H2<\/sub>O
\nThe less soluble Na2<\/sub>SO4<\/sub> is removed by filtration.<\/p>\n

Step – 3 : Conversion of sodium dichromate into potassium dichromate: The solution of sodium dichromate is treated with Kcl to give potassium dichromate.
\nNa2<\/sub>Cr2<\/sub>O7<\/sub> + 2Kcl \u2192 K2<\/sub>Cr2<\/sub>O7<\/sub> + 2Nacl<\/p>\n

Question 25.
\nExplain the hybridization, geometry and magnetic property of [CoF6<\/sub>]3-<\/sup> on the basis of valence bond theory [ Z of Go = 27]
\nAnswer:
\n\"2nd
\nGeometry f[Co (NH3<\/sub>)6<\/sub>]3+<\/sup>
\nMagnetic property: paramagnetic<\/p>\n

Question 26.
\na) Write any two postulates of erner\u2019s theory of Co- ordination compounds.
\nAnswer:
\nPostulates :<\/p>\n

1. Central metal ion in a complex shows two types of valences – primary valence and secondary valence.<\/p>\n

2. The primary \u201calence is ionisable and satisfied by negative ions.<\/p>\n

3. The secondary valence is non ionisable. It is equal to the coordination number of the central metal ion or atom. It is fixed for a metal. Secondary valences are satisfied by negative ions or neural molecules (ligands).<\/p>\n

4. The primary valence is non directional. The secondary valence is directional. Ions or molecules attached to satisfy secondary valences have characteristic spatial arrangements. Secondary valence decides geometry of the complex compound,<\/p>\n

b) Write the IUPAC name of [pt(NH3<\/sub>)3<\/sub>(H2<\/sub>O)Cl2<\/sub>]
\nAnswer:
\nTriamine dicloro platinum hydrate.<\/p>\n

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

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

Question 27.
\na) Calculate the packing efficiency in a body centered cubic (BCC) lattice.
\nAnswer:
\nIn a BCC unit cell, the edge length is \u2018a\u2019 and radius of the particle is \u2018r\u2019.
\nThen r = \\(\\frac{\\sqrt{3}}{4} \\mathrm{a}\\) \u2234 a = \\(\\frac{41}{\\sqrt{3}}\\)
\nand two particles are present in an unit cell of BCC<\/p>\n

\"2nd<\/p>\n

b) Silver forms a ccp lattice the edge length of his unit cell is 408.6 pm calculate the density of silver (NA<\/sub> = 6.022 \u00d7 1023<\/sup> )
\nAnswer:
\n\"2nd
\nd = 4 \u00d7 107.9\/(4.08)3<\/sup> \u00d7 10-24<\/sup> \u00d7 6.022 \u00d7 1023<\/sup>
\nd = 431.6\/40.899
\nd= 10.5528g\/cm3<\/sup><\/p>\n

\"KSEEB<\/p>\n

Question 28.
\na)5.8g of a non volatile solute was dissolved in 100 g carbon disulphide ( CS2<\/sub> ) The vapour pressure of the solution was found to be 190mm of Hg calculate the molar mass of the solute given the vapour pressure of pure CS2<\/sub> is 195 mm of Hg [ Molar mass of CS2<\/sub> = 76gmol-1<\/sup>] (3)
\nb) Mention any two differences between Ideal and non ideal solutions (2)
\nAnswer:
\nIdeal solution<\/p>\n

    \n
  1. The inter moleculor interactions between the components of the solution are similar to those found in the pure components<\/li>\n
  2. Ther is no volume change during mixing ((Av = o)<\/li>\n
  3. Obeys raoult\u2019s law of solution<\/li>\n<\/ol>\n

    Non ideal solution<\/p>\n

      \n
    1. The inter molecular interaction between the components of the solution are different from those found in the pure components<\/li>\n
    2. Volume of the solution is either less or more than the total volume of the components mixed<\/li>\n
    3. Does not obey raoult\u2019s law of solution either positive or negative devistion<\/li>\n<\/ol>\n

      Question 29.
      \na)State faradays first law of electrolysis write its mathematical from using usual notations. (2)
      \nAnswer:
      \n\"2nd<\/p>\n

      b) State Kohlrausch law (2)
      \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)
      \nWrite the overall cell reaction taking place in Daniel cell (1)
      \nAnswer:
      \n\"2nd
      \nZn(s)<\/sub> +Cu2+<\/sup>(aq)<\/sub> \u2192 Zn2+<\/sup>(aq)<\/sub> + Cu(s)<\/sub><\/p>\n

      Question 30.
      \na) Derive the integrated rate equation for the rate constant of a Zero order reaction. (3)
      \nAnswer:
      \nConsider a zero order reaction
      \nR \u2192 P
      \n\"2nd
      \n[R] = -Kt + I …………. (1)
      \nWhere I is the integration constant
      \nwhen t = o then [R] = [R]
      \n\u2234 [R]0<\/sub> = -K \u00d7 0 + I
      \n\u2234 I = [R]0<\/sub>
      \nSubstituting the value of I in eq (1)
      \nR] = -Kt + [R]0<\/sub>
      \nKt= [R]0<\/sub> – [R]
      \n\"2nd<\/p>\n

      \"KSEEB<\/p>\n

      b. Draw a graph of potential energy v\/s reaction coordinate showing the effect of a catalyst on activation energy.
      \nAnswer:
      \n\"2nd<\/p>\n

      Question 31.
      \na) Mention any three differences between lyophilic and lyophobic colloids (3)
      \nAnswer:
      \nProperty<\/p>\n

        \n
      1. Affinity towards dispersion medium.<\/li>\n
      2. Method of preparation.<\/li>\n
      3. Stability<\/li>\n<\/ol>\n

        Lyophilic<\/p>\n

          \n
        1. 1. High affinity.<\/li>\n
        2. Easily formed on mixing or heating the dispersed phase with dispersion medium.<\/li>\n
        3. stable.<\/li>\n<\/ol>\n

          Lyophobic<\/p>\n

            \n
          1. Low affinity<\/li>\n
          2. Special methods are used.<\/li>\n
          3. Highly unstable.<\/li>\n<\/ol>\n

            b) What is heterogeneous catalysis ? give an example ? (2)
            \nAnswer:
            \nA catalytic process in which reactants and catalyst are in different phases are known as heterogenous catalysis.
            \nE.g: 1.
            \n\"2nd
            \nHere the reactants are gases, catalyst iron is a solid
            \n\"2nd
            \nHere reactants and catalyst are in different phases.<\/p>\n

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

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

            Question 32.
            \na) Explain the mechanism of SN<\/sub> 1 reaction taking 2- bromo – 2 methyl propane (t – butyl bromide) (2)
            \nAnswer:
            \n\"2nd
            \nRate of the reaction depends on slow step of the reaction r \u03b1 [(CH3<\/sub>)3<\/sub>C Br]1<\/sup>
            \nOrder =1<\/p>\n

            b) Explain Wurtz – Fittig\u2019s reaction. (2)
            \nAnswer:
            \nA mixture of an alkyl halide and aryl halide gives an alkylarene when treated with sodium in dry ether and is called as wurtz – fitting reaction.<\/p>\n

            c) Write the general formula of grignard reagent (1)
            \nAnswer:
            \nR-Mg- X, where \u2018R\u2019 is alkgl or aryl group and \u2018X\u2019 is hologen atom<\/p>\n

            \"KSEEB<\/p>\n

            Question 33.
            \na) How is phenol manufactured by cumene process ? (3)
            \nAnswer:
            \nCumene is oxidised by oxygen to form cumene hydroperoxide. Which on acid hydrolysis gives phenol
            \n\"2nd<\/p>\n

            b) Among alcohols and phenols which one is more acidic ? and why ? (2)
            \nAnswer:
            \nIn phenol charge because of resonance this facilitates the heterolytic eleavage of – OH bond resulting in the* formation of phenoxide ion the benzene ring with draws the negative charge from oxygen atom hence phenutide ion formed is resonance stabilizes dne to this phenols are acidic in nature.<\/p>\n

            But in alchohols neither does oxygen of- OH group acquire positive change nor is the alkoxide ion is resonance stabilized in addition to this oxygen in alchols is attached to elestron donating alkyl groups these electron donating groups decrease the stability of alkoxide ion hence alchok are not acidic<\/p>\n

            Question 34.
            \na) Explain the mechanism of addition of HCN of a carbonyl in presence of a base. (3)
            \nAnswer:
            \n\"2nd<\/p>\n

            b) How is benzamide obtained from benzoic acid ? (2)
            \nAnswer:
            \nBenzamide from benzoic acid.<\/p>\n

            \"KSEEB<\/p>\n

            Question 35.
            \na) Explain carbyl amine reaction
            \nAnswer:
            \ncarbyl amine reaction when primary amine is heated with a mixture of chlorofrom and alcholic solution of potasium hydroxide, chloroform and isocyanide having an into lerable smell is formed.
            \n\"2nd
            \n3HCL + 3KOH \u2192 3KCL + 3H2<\/sub>O
            \nR – NH2<\/sub> + CHCL3<\/sub> \u2192 R – NG + 3KCL + 3H2<\/sub>O<\/p>\n

            b) What is the action of bromine water on benzenamine (Aniline) at room temp
            \nAnswer:
            \nAction of bromine water on benzenamine (Aniline) at room temperature 2,4,6 – tribromoanile.<\/p>\n

            c) The pkb valuse of Ammonia methanamine and bezenamine (aniline) are 4.75, 3.38 & 9.38 respectively arrange them in the increasing order of their basic strength
            \nAnswer:
            \nMethanamine > benzenamine > ammoxia<\/p>\n

            Question 36.
            \na) How do you show that glucose contains a linear chain of six carbon atoms. (2)
            \nb) What are essential amino acids ? is glyeine an essential amino acid ? (2)
            \nAnswer:
            \nBased of dietary requirement they are classified into essential and Non – essential amino acids :<\/p>\n

            Essential amino acids : Amino acids that cannot be synthesised in the body, and must be obtained through diet. Example – Valine, leucine, isoleucine.<\/p>\n

            Non – essential amino acids: Amino acids that can be synthesised in the body.
            \nExample – Glycine, alanine, gutamic acid Non – essential amino acids.<\/p>\n

            c) Write the general formula of Zwitter ionic form of an amino acid
            \nAnswer:
            \n\"2nd<\/p>\n

            \"KSEEB<\/p>\n

            Question 37.
            \na) Explain addition polymerization with an example.
            \nAnswer:
            \nA polymer formed by the addition of repeating monomer units possessing double or triple bond without elimination of by product molecule during polymerization is called addition polymer.
            \n\"2nd<\/p>\n

            b) Name the monomers used in the manufacture of Nylon- 6, 6.
            \nAnswer:
            \nMonomer of Nylon 6, 6 – Hexamethylene diamine and Adipic – acid.
            \nPartial structure – [-OC-(CH2<\/sub>)4<\/sub>-CONH-(CH2<\/sub>)6<\/sub> – NH-]n<\/sub><\/p>\n

            c) Write the partial structure of Neoprene
            \nAnswer:
            \n\"2nd<\/p>\n","protected":false},"excerpt":{"rendered":"

            Students can Download 2nd PUC Chemistry Model Question Paper 4 with Answers, 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 Model Question Paper 4 with Answers 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\/18075"}],"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=18075"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/18075\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=18075"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=18075"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=18075"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}