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ISC Class XII Board Exam 2013 : Chemistry

20 pages, 68 questions, 0 questions with responses, 0 total responses,    0    0
Mohammed Malik Sharaf
Holy Innocents High School (HIHS), Wellington
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%/$1. 3$*( ! " ! " ! %3.4 6)45-10 (a) Fill in the blanks by choosing the appropriate word/words from those given in the brackets: (zero, first, second, increased, decreased, anode, cathode, active, inactive, potassium cyanide, internal, external, dependent, independent, red, benzoic acid, benzoin, common ion effect, salt hydrolysis, alkali, potassium hydroxide.) (i) In a galvanic cell, electrons flow from_________ to _______ through the connecting wires. (ii) Racemic mixtures are optically _________ because of _________ compensation. # $ (iii) Half life period of a _________ order reaction is _________ of the concentration of the reactant. (iv) Benzaldehyde when treated with an alcoholic solution of_______ forms _______. (v) (b) Solubility of calcium oxalate is ________ in the presence of ammonium oxalate because of ___________. Complete the following statements by selecting the '133)'5 %/5)30%5-7) from the # $ choices given: (i) The compound which is optically active is: (1) 1-butanol (2) 2-butanol (3) 1-propanol (4) 2-methyl-1-propanol (ii) The salt which will not hydrolyse in aqueous solution is: (1) Copper sulphate (2) Sodium sulphate (3) Potassium cyanide (4) Sodium carbonate (iii) Copper has the face centred cubic structure. The coordination number of each ion is: (1) 4 (2) 12 www.guideforschool.com (3) 14 (4) 8 (iv) For the reaction 2SO2 + O2 2SO3 , the unit of equilibrium constant is: (1) L mol-1 (2) J mol-1 (3) mol L-1 (4) [L mol-1]2 (v) The deficiency of vitamin D causes: (1) Rickets (2) Gout (3) Scurvy (4) Night blindness. (c) Answer the following questions: (i) # $ Two metallic elements A and B have the following standard oxidation potentials: A = 0 40v B = 0 80v. What would you expect if element A was added to an aqueous salt solution of element B? Give a reason for your answer. (ii) Two moles of NH3 are introduced into one litre flask in which it dissociates at high temperature as follows: 2NH3(g) N2(g) + 3H2(g). Determine Kc, if at equilibrium 1 mole of NH3 remains. (iii) Give balanced equation for the preparation of salicylaldehyde from phenol. (iv) If the half life period for a first order reaction is 69 3 seconds, what is the value of its rate constant? (v) (d) Define cryoscopic constant. Match the following: (i) (ii) (iii) (iv) (v) Colligative property Nicol prism Activation energy Starch Acetaldehyde # $ (a) (b) (c) (d) (e) Polysaccharide Osmotic pressure Aldol condensation Polarimeter Arrhenius equation www.guideforschool.com Comments of Examiners (a) (i) Some candidates wrote cathode to anode . (ii) Many candidates wrote active and internal in place of the correct words. (iii) Some candidates wrote dependent in place of independent . (iv) Many candidates wrote potassium hydroxide and Benzoic acid instead of the correct words. (v) A few candidates wrote increased in place of decreased . (b) (i) 1-butanal or 2-methyl propanol was chosen by some candidates. (ii) Potassium cyanide or sodium carbonate was chosen in some cases. (iii) Some candidates wrote 4 in place of the correct option. (iv) Many candidates chose the options (3) and (4). (v) A few candidates chose scurvy or night blindness . (c) (i) Candidates were confused with oxidation and reduction potential. Some wrote B displaced A and various other wrong answers and incorrect reasons. (ii) Most of the candidates calculated Ke for 2 moles of NH3. Unit was wrong in many scripts. (iii) Wrong reagents were used by many candidates. In some cases, the equation was unbalanced. (iv) Several candidates used a wrong formula. (v) Most of the candidates gave the mathematical expression and explained that. (d) Most of the candidates were able to attempt this part correctly. The concept of production of current and flow of electrons in a galvanic cell should be explained clearly. The idea of internal and external compensation should be taught with correct examples. Reactions should be practiced in class with correct names of the reactants and products. Common ion effect should be taught in class with equations showing the shift of equilibrium. The concept of chiral carbon atom should be made clear. Isomerism should the practised with examples. The units of Ke should be derived in class taking examples. The use of electrochemical series should be taught in details giving its importance in determining the properties and nature of the elements. Reactions should be practiced with correct reactions and products in the balanced form. 6)45-10 (a) (b) (i) anode, cathode (ii) inactive, external (iii) first \ 1st , independent or zero, dependent or second dependent (iv) potassium cyanide, benzion/ formula (v) decreased, common ion effect (i) 2 butanol / formula (ii) (1) Sodium sulphate / formula www.guideforschool.com (iii) (2) 12 /twelve (iv) (1) L mol-1 (v) (1) Rickets Answer the following questions: (c) (i) A displaces B from its salt solution. Standard reduction potential of A is less than standard reduction potential of B or any other explanation. (ii) 2 NH3 N2+3H2 Initial 2 0 At eqn. 1 1 0 3 2 2 1 [NH3] = 1 moles per litre [N2] = 2 moles per litre 1 1 3 2 moles per litre 1 [H2] = N 2 H 2 3 Kc = NH3 2 = (iii) (v) (d) 1 2 3 K= mole 4 / litre 4 mole 2 / litre 2 27 mole 2 / litre 2 = 1 687 (mol / lit)2 16 OH OH O (iv) 1 3 2 2 + CHCl3+ 3NaOH O CHO + 3NaCl + 2H2O (OR with KOH) 0.693 0.01sec 1 693 Depression of freezing point when the molality of the solution is unity / any correct definition. Match the following: (i) (b) Osmotic pressure (ii) (d) Polarimeter (iii) (e) Arrhenius equation (iv) (a) Polysaccharide (v) (c) Aldol condensation www.guideforschool.com ! %3.4 4-9 581 581 581 ! 581 6)45-10 (a) (i) Ethylene glycol is used as an antifreeze agent. Calculate the amount of ethylene # $ glycol to be added to 4 kg of water to prevent it from freezing at -6oC. (Kf for H2O = 1 85 K mole-1 kg) (ii) The freezing point of a solution containing 0 3gms of acetic acid in 30gms of # $ benzene is lowered by 0 45K. Calculate the Van t Hoff factor. (at. wt. of C = 12, H = 1, O = 16, Kf for benzene = 5 12K kg mole-1). (b) Name the law or principle confirmed by the following observations: # $ (i) When water is added to 0 01M aqueous solution of acetic acid the number of hydrogen ions increase. (ii) When 96500 coulombs of electricity is passed through acidulated water, 5 6 litres of oxygen at s.t.p. is liberated at the anode. (c) Arrange Ag, Cr and Hg metals in the increasing order of reducing power. Given: 0 80V Eo Ag E Ag 0 74V o cr 3 cr 0 79V Eo Hg 2 (d) # $ Hg In a first order reaction, 10% of the reactant is consumed in 25 minutes. Calculate: (i) The half life of the reaction. (ii) The time required for completing 17% of the reaction. Comments of Examiners (a) (i) Incorrect formula and substitution was done by many candidates. Some candidates were unable to calculate the molecular weight of glycol. (ii) Many candidates made wrong calculations due to wrong substitution. (b) (i) Many candidates gave the answer as, dilution law instead of Ostwald dilution Law. (ii) Some candidates wrote only Faraday s law but did not mention the 2nd law . www.guideforschool.com # $ More practice should be given in numericals along with correct substitution. Important laws and their applications should be taught in class with correct examples. Elechochemical series should be taught with reference to the properties of the elements. (c) Several candidates were confused between reduction and reduction potential . Many candidates arranged the metals in the reverse direction. (d) (i) Some candidates made calculation errors in this part of the question. (ii) Incorrect formula was taken by some candidates. 6)45-10 (a) (i) Tf K f w= w 1000 m W CH2OH [Mol. wt. of CH2OH Tf m W K f 1000 = 6 62 4 1000 1 85 1000 = 804 32 g (ii) Tf iK f i w 1000 or T f = ikf x m m W Tf m W K f w 1000 = 0 45 60 30 5 12 0 3 1000 = 0 527 (b) (i) (ii) (c) (d) Ag, Hg, Cr Ostwald s dilution law Faraday s second law K= 2 303 a log t a x K= 2 303 100 log 25 90 = 4.215 10-3 min-1 Half life (t ) = t= = 0.693 0.693 164.41 minutes K 4.215 10 3 2 303 a log k a x 2 303 100 log = 44.21 minutes 3 4.215 10 83 www.guideforschool.com = 62 ] 6)45-10 (a) (b) (c) Explain giving reasons why (Give equations in support of your answer): (i) A solution of NH4Cl and NH4OH acts as a buffer. (ii) Cu is precipitated as CuS while Zn is not precipitated when H2S is passed through # $ an acidic solution of Cu(NO3)2 and Zn(NO3)2 respectively. (i) What is Schottky defect in a solid? (ii) A bcc element (atomic mass 65) has a cell edge of 420 pm. Calculate its density # $ in gms/cm3. The rate of the reaction H2+I2 # $ # $ 2HI is given by: # $ rate = 1 7 10-19[H2][I2] at 25oC. The rate of decomposition of gaseous HI to H2 and I2 is given by: rate = 2 4 10-21[HI]2 at 25oC. Calculate the equilibrium constant for the formation of HI from H2 and I2 at 25oC. Comments of Examiners (a) (i) The definition of Buffer solution was given by many candidates instead of explaining Buffer action . (ii) Many candidates did not mention the low Ksp for CuS and high Ksp for ZnS. Some candidates did not mention the suppression of concentration of Sulphide ion in acidic medium. (b) (i) Many candidates did not mention the missing of both anion and cation in ionic crystals. Some candidates confused it with Frenkel defect. (ii) Several candidates did not attempt this numerical, while some others did the problem with incorrect formula. In some cases, the value of Z was taken wrongly. (c) Value of Kc was taken as rate1 / rate2, giving wrong answers. 6)45-10 (a) (i) NH4Cl NH4+ (High) + Cl- (High) NH4OH NH4+ (low) + OH- (low) Addition of HCl, HCl H+ + Cl- H+ (from HCl) + OH- (from NH4OH) H2O OH- ions are removed from the solution. www.guideforschool.com The mechanism of buffer action should be explained with reference to the addition of acid, alkali and dilution. Explanation should be given taking correct equation. The use of solubility product in salt analysis should be taught with correct examples. Stress should be laid on key words. Defects in crystals should be explained diagrammatically. Adequate practice should be given in numericals. In the absence of OH-, NH4OH, dissociates more in giving more OH- ions. These OHions combines with H+ to form water. Process keeps on happening till all H+ ions are consumed and pH remains constant. Addition of NaOH: NaOH Na+ + OH- NH4+ (from NH4Cl) + OH- (from NaOH) NH4OH NH4OH being a weak base dissociates partially and whatever OH- are released are not sufficient to increase the pH. OR any other explanation. (ii) H+ + Cl- . H2S HCl 2H++ S2- In the presence of HCl, the dissociation of H2S is suppressed due to common H+ ion and less S2- ions are released in solution. The Ksp of CuS is low and hence [Cu+2][S2] > Ksp. ZnS has a high value of Ksp and hence, does not get precipitated with less S2- ions. (b) (i) (ii) Schottky defect pair of holes exist in the crystal lattice due to one positive ion and one negative ion being absent from the crystal lattice. OR any other definition Density (P) = = = Z M NA a3 2 65 6.023 1023 420 10 10 3 2 65 6.023 1023 7 4 10 23 = 2.91 gms/cm3 (c) H2 + I2 2HI K1 = 1 7 10-18 K2 = 2 4 10-21 Kc K1 1 7 10 18 708 102 21 K 2 2 4 10 6)45-10 (a) (b) (i) Give Lewis definition for acids and bases. (ii) The solubility of Ag2CrO4 at 25oC is 8 0 10 5 moles/litre. Calculate its solubility # $ product. (i) Define molar conductance of a solution. State its unit. How is it related to the # $ specific conductance of a solution? www.guideforschool.com # $ (ii) Calculate the value of Ecell at 298K for the following cell: Al / Al 3+ E o 3 1 66 volt and E o Al (c) (0 01M) // Sn (0 015M) / Sn Sn 2 Al 0 14 volt Sn (i) # $ Calculate the degree of hydrolysis of 0 2(M) sodium acetate solution. -10 (Hydrolysis constant of sodium acetate = 5 6 10 and ionic product of H2O = 10-14 at 25oC) (ii) Explain why high pressure is used in the manufacture of ammonia by Haber s # $ process. State the law or principle used. Comments of Examiners (a) (i) Several candidates wrote electron acceptor instead of stating electron pair acceptor . (ii) Wrong formula was used by some candidates. (b) (i) Many candidates explained the formula of molar conductance in place of defining it. The unit was given wrongly in many scripts. (ii) Several candidates calculated E0cell correctly but the calculation of Ecell was wrong. Some got the same values for both since they rounded up the value instead of calculating it up to the third place of decimal. Many candidates did wrong substitution in the Nernst equation. (c) (i) Incorrect formula was used by many candidates. (ii) The explanation given by many candidates was not clear. In some cases, Le Chatelier s principle was only mentioned but not stated. Lewis definition should be correctly taught with correct examples. Derivation of the Ksp values of different salts should be done in class. Nernst equation should be taught with correct examples and correct substitution. Numericals should be practised with correct formula of substitution. Le Chaterliers principle should be explained with reference to the equations mentioned in the scope of syllabus. 6)45-10 (a) # $ 2+ (i) Lewis acid is an electron pair acceptor. Lewis base is an electron pair donor. (ii) Ag2CrO4 S 2Ag+ + CrO42-= 2S S Ksp = [Ag+]2[CrO42-] = (2S)2 (S) = 4S3 Ksp = 4 (8 10-5)3 = 2 048 10-12 www.guideforschool.com (b) (i) Molar conductance is defined as the conducting power of all the ions produced by dissolving one gm mole of an electrolyte in solution/ any other definition Its unit is ohm-1 cm2 mole-1 or ohm-1 m2 mole-1 ^m = 1000 ^ sp c c = conc. in molarity (ii) E ocell E oredn cathode E oredn anode = (-0 14) (1 66) volt = 1 52 volt Ecell = E ocell products 0 05912 log n Reactants Al 3e Al3+ x (2) Sn2+ + 2e Sn x (3) 2Al 6e 2Al3+ 3Sn2+ + 6e 3 Sn 2Al + 3Sn2+ 2Al3+ + 3 Sn Ecell = 1 52 0 05912 [Al3 ]2 [Sn]3 log volt 6 [Al]2 [Sn 2 ]3 0 01 1 volt 0 05912 log 2 = 1 52 3 6 1 0015 2 3 (1 52 - 0 0145) volt = 1 5055 volt (c) (i) h= = (ii) kw Kh ka.c c 5 6 10 10 0 2 = 5 29 10 5 Formation of ammonia takes place with decrease in volume. Hence, the reaction is favoured with high pressure. Le Chatelier s Principle when a system at equilibrium is subjected to a stress, the equilibrium shifts in that direction to nullify the effect of the stress OR any other explanation. www.guideforschool.com ! 581 6)45-10 (a) (b) (c) Give the IUPAC names of the following coordination compounds: (i) K2[Zn(OH)4] (ii) [Co(NH3)5(CO3)]Cl # $ For the complex ion [Fe(CN)6]3 state: (i) The geometry of the ion. (ii) The magnetic property of the ion. # $ What type of structural isomers are [Co(NH3)5Br]SO4 and [Co(NH3)5SO4]Br ? Give a chemical test to distinguish the isomers. Comments of Examiners (a) (i) Several candidates wrote hydroxy in place of hydroxo . The valency of Zinc was not given correctly by a number of candidates. (ii) Several candidates made mistakes in writing the correct name. Carbonate was written instead of Carbonato . The oxidation state of cobalt was given incorrectly by some candidates. (b) (i) Many candidates wrote tetrahedral or bipyramidal . (ii) Some candidates gave the answer as diamagnetic . (c) Many candidates wrote linkage isomerism . Chemical test was not given but the ionisation of the two compounds was shown. # $ Many examples of co-ordination complexes should be practised with correct spelling and correct oxidation state. Geometry of co-ordination compounds and ions should be explained by drawing the correct structure. The relation of the magnetic property with number of unpaired electrons should be explained by writing the electronic configuration in box diagrams. 6)45-10 (a) (b) (i) potassiumtetrahydroxo zincate(II) (ii) pentaamminecarbonatocobalt(III) chloride (i) Octahedral, Paramagnetic (ii) Ionisation isomerism. [Co(NH3)5Br]SO4 gives white ppt with BaCl2 solution, but [Co(NH3)5 SO4]Br does not give white ppt. with BaCl2 solution OR any other test. (c) Type of structural isomers and correct chemical test. www.guideforschool.com 6)45-10 (a) For the molecule XeF2 : # $ (i) Draw the structure of the molecule indicating the lone pairs. (ii) State the hybridisation of the central atom. (iii) State the geometry of the molecule. (b) Give balanced chemical equations for the following reactions: (i) Fluorine treated with dilute sodium hydroxide solution. (ii) Hydrogen sulphide treated with concentrated sulphuric acid. # $ (iii) Potassium iodide treated with acidified potassium permanganate solution. Comments of Examiners (a) (i) Proper orientation of the orbitals around the Xenon atom was not shown by many candidates. Lone pair of electrons was missing in some cases. (ii) The hybridisation was given incorrectly by many candidates. (iii)Some candidates gave the answer as T shaped. The word linear was missing in many answers. (b) In this part, many candidates wrote unbalanced and incorrect equations. Structures of the compounds should be explained by drawing and showing the lone pair of electrons. The correct hybridisation should be taught by writing the electronic configuration in box diagrams. The geometry of the molecules should be explained on the basis of hybridisation. Students should be given practice in writing correct balanced equations. 6)45-10 (a) oo F Xe F oo oo sp3d, linear. (b) (i) 2F2 + 2NaOH F2O + 2NaF + H2O (ii) H2S+ H2SO4 2 H2O + SO2 + S (iii) 2KMnO4 + 8H2SO4 + 10 KI 6K2SO4 + 2MnSO4 + 8H2O + 5I2 www.guideforschool.com 6)45-10 (a) (b) In the extraction of zinc from zinc blende: # $ (i) Give an equation to show how zinc oxide is converted to zinc. (ii) How is impure zinc finally electro-refined? Explain why: # $ (i) Transition elements form coloured compounds. (ii) Interhalogen compounds are more reactive than their constituent elements. (iii) Cu+ is diamagnetic but Cu2+ is paramagnetic. (Z = 29) Comments of Examiners (a) (i) Some candidates wrote CO2 in place of CO . (ii) The electrolyte was given wrongly by many candidates. (b) (i) The presence of unpaired d-electrons was not mentioned by many candidates. (ii) The polar nature of the x-y bonds or less overlapping of the orbitals was not mentioned by several candidates. (iii)The diamagnetic nature of Cu+ was not mentioned by several candidates. Electrorefining should be taught with correct electrodes and electrolytes. The properties of transition metals should be explained with reference to the d-electrons. Magnetic nature should be explained in terms of electronic configuration. 6)45-10 (a) (i) ZnO + C 1673K Zn + CO (ii) Anode Impure Zn block Cathode Thin sheet of pure Zinc Electrolyte ZnSO4 solution containing a little dilute H2SO4 Cathode Zn2+ + 2e Zn (b) (i) (ii) (iii) Anode Zn 2e Zn+2 Presence of unpaired electrons in d orbitals/ d-d transition Electrons absorb radiations of one colour from white light for excitation from one energy level to another within the same d subshell. Hence, transmitted light appears coloured. Or any correct explanation x y bonds are weaker than x x or y y bonds. Polar nature of x-y bond. Less overlapping of orbitals in x y bond. Cu+1 has no unpaired electrons, hence diamagnetic Cu+2 has unpaired electrons, hence paramagnetic www.guideforschool.com ! 581 6)45-10 (a) (b) How can the following conversions be brought about: (i) Nitro benzene to benzene diazoniumchloride. (ii) Propanoic acid to ethylamine. # $ (iii) Benzoic acid to benzaldehyde. # $ Identify the compounds A, B, C, D, E and F: # $ HC CH # $ CH 3COONa dil.H 2SO 4 SOCl2 [O] [A] [B] [C] [D] 2 Hg NH2OH C6H5OH [E] [F] Comments of Examiners (a) (i) Many candidates used LiAlH4 or H2 /Ni for the reduction of nitrobenzene to aniline. In some cases, reagents and temperature were not mentioned for diazotization. (ii) Several candidates started the conversion from ethanoic acid in place of propanoic acid. Conversion steps were incorrect in many cases. (iii)Most of the candidates reduced benzoic acid to benzaldehyde directly by metal / acid. (b) [E] was identified as methylamine and [F] as ethylacetate by many candidates. Reduction of nitrobenzene should be taught with correct reducing agent. Diazotization should be taught with correct reagents and temperature (0oC 50C). Aliphatic and aromatic conversions should be practiced in class with correct reagents. Reactions should be practiced in class with correct reactants and products. 6)45-10 (a) (i) NO2 O (ii) (iii) Conc. Sn + HCl NH2 [H] O CH 3CH 2 COOH NH 3 N 2 Cl NaNO2 O dil. HCl 0 to 5oC CH 3CH 2CONH 2 Br2 / KOH H2 C 2 H 5 NH 2 SOCl2 Pd C6 H 5COOH C6 H 5COCl C6 H 5CHO BaSO 4 PCl3 /PCl5 www.guideforschool.com (b) [A] Acetaldehyde or CH3CHO [B] Acetic acid or CH3COOH [C] Acetyl chloride or CH3COCl [D] Acetic anhydride or (CH3CO)2O [E] Acetaldoxime or CH3CH=NOH [F] Phenyl acetate or C6H5OCOCH3 OR any common name 6)45-10 (a) (b) (c) Write balanced chemical equations for the following reactions and name the reactions: (i) Acetamide is heated with bromine and sodium hydroxide solution. (ii) Benzaldehyde is treated with 50% sodium hydroxide solution. Give one chemical test to distinguish between the following pairs of compounds: (i) Acetone and phenol. (ii) Formic acid and Acetic acid. (i) Name the type of isomerism exhibited by the following pairs of compounds: (ii) (1) (C2H5)2NH and CH3- NH-C3H7 (2) 1-butanol and 2 methyl-1-propanol Name the type of isomerism that the compound with molecular formula C3H6O2 exhibits. Represent the isomers. Comments of Examiners (a) (i) Only the main product was written by many candidates while the by products were missing. In some cases, the equation was not balanced. (ii) The name of the reaction was given incorrectly by a number of candidates. (b) (i) Many candidates gave ferric chloride test for a acetone. Some only mentioned the name of the test without giving the observation. (ii) Incorrect tests were given by many candidates. (c) (i) Some candidates gave the answer as position isomers . (ii) Most of the candidates were able to attempt this part correctly. www.guideforschool.com # $ # $ # $ # $ Name equations should be taught in balanced form. Reactants and products should be correctly taught. Identification of organic compounds should be done in class with correct tests. Isomerism should be explained by drawing the structural formulae of the isomers. 6)45-10 (a) O (i) CH3 C NH2 + Br2 + 4NaOH CH3NH2 + 2NaBr + Na2CO3+ 2H2O Hoffmann s bromanide or Hofmann s degradation reaction. (ii) 2C6H5 CHO dil. NaOH + C6H5CH2OH+ C6H5COONa Cannizzaro s reaction (b)(i) Acetone when treated with I2 + NaOH gives yellow ppt. of CHI3 but phenol with I2 + NaOH gives no such ppt. Phenol with neutral FeCl3 solution gives violet colouration but Acetone gives no such observation (Or any correct test) (ii) Formic acid gives white or grey ppt. with HgCl2 solution but Acetic acid does not give such observation (Or any correct test)b (c) (i) (1) Metamerism (2) Chain isomerism (ii) Functional isomerism: O // CH3 CH2 C \ OH Optical Isomerism: OH H CH3 C C H O O CH3 C OCH3, HCOOC2H5 H OH C C CH3 O H 6)45-10 (a) Write balanced chemical equations for the following reactions: (i) Oxalic acid is treated with acidified potassium permanganate solution. (ii) Benzoic acid is treated with a mixture of concentrated nitric acid and concentrated sulphuric acid. (iii) Methyl magnesium iodide is treated with carbon dioxide and the product hydrolysed in acidic medium. (iv) Ethylacetate is treated with ammonia. www.guideforschool.com # $ (b) An organic compound [A] having molecular formula C2H7N on treatment with nitrous acid gives a compound [B] having molecular formula C2H6O. [B] on treatment with an organic compound [C] gives a carboxylic acid [D] and a sweet smelling compound [E]. Oxidation of [B] with acidified potassium dichromate also gives [D]. (i) Identify [A], [B], [C], [D] and [E]. (ii) (c) Write balanced chemical equation of [D] with chlorine in the presence of red phosphorus and name the reaction. Acetamide is amphoteric in nature. Give two equations to support this statement. # $ # $ Comments of Examiners (a) (i) A number of candidates wrote incorrect equations. Equation should be studied by (ii) Ortho - para benzoic acid was written as the writing the reactants and products product by several candidates. with balanced form. (iii) Some candidates wrote wrong products in this Organic problems of part. identification should be given in (iv) This part was generally done correctly by class. candidates. The amphoteric nature of (b) (i) Identification of [C] was incorrectly done by acetamide should be taught several candidates. correctly with proper reactants (ii) A number of candidates wrote unbalanced and products. equations. (c) Many candidates did not attempt this part of the question. Some gave the reaction with NaOH to show the acidic nature of acetamide. 6)45-10 (a) (i) (ii) 5COOH + 2KMnO4 + 3H2SO4 10CO2 + K2SO4 + 2MnSO4 + 8H2O COOH COOH O conc. conc. + HNO3+ H2SO4 COOH O + H2O NO2 (iii) (iv) CH3MgI + O = C = O [IMgO = O] CH3COOH + MgI(OH) CH3COOC2H5 + NH3 CH3CONH2+ C2H5OH 3 www.guideforschool.com (b) (i) [A] CH3CH2NH2 or Ethylamine [B] CH3CH2OH or Ethanol [C] (CH3CO)2O or Ethanoic anhydride [D] CH3COOH or Ethanoic acid. [E] CH3COOC2H5 or Ethyl ethanoate. (ii) CH3COOH +Cl2 Re d P CH2ClCOOH+HCl Hell Volhard Zelinsky reaction or HVZ reaction. Basic : CH3CONH2+HCl CH3CONH2.HCl or [CH3CONH3]+Cl- (c) Acidic: CH3CONH2 + HgO (CH3CONH)2Hg+H2O ! % !12-'4 *160( (-**-'6/5 &: '%0(-(%5)4 -0 5,) 6)45-10 %2)3 Co-ordination compounds. Definitions of different terms and units. Isomerism. Buffer solution Electrochemical cells. Geometry and hybridization. Inorganic equations. & 10')254 &)58))0 8,-', '%0(-(%5)4 +15 '10*64)( ' Hydrolysis of salts. Catalysts in organic reactions. Conversion in Organic Chemistry. Numericals in Colligative properties with correct units. 6++)45-104 *13 456()054 Practice organic conversions. Study chemical tests to distinguish between organic compounds. Study isomerism by drawing the structural formulae of the isomers. Avoid selective studies. Practice equations, both inorganic and organic with balanced form and correct condition. Practice numericals from all chapters with correct formulae and units. www.guideforschool.com

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