Section-I [40 Marks]<\/strong> Question 1. (b) Choose the correct answer from the options given below: [5] (ii) If the molecular formula of an organic compound is CioH18 it is: (iii) Which of the following is a common characteristic of a covalent compound? (iv) To increase the pH value of a neutral solution, we should add: (v) Anhydrous iron(III) chloride is prepared by: (c) Identify the substance underlined, in each of the following cases: [5] (d) Write a balanced chemical equation for each of the following: [5] (e) State one relevant observation for each of the following reactions: [5] (f) (i) Draw the structural formula for each of the following: [5] (g) (i) Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23). [5] (ii) Molecular mass of CUSO4<\/sub>.5H2<\/sub>O (iii) E.F. = XY2<\/sub> (h) Match the atomic number 2,4, 8,15, and 19 with each of the following: [5] Section – II [40 Marks]<\/strong> Question 2. (b) State the type of Bonding in the following molecules: [2] (c) Answer the following questions: [2] (d) Identify the salts P and Q from the observations given below: [2] Question 3. (b) State the observations at the anode and at the cathode during the electrolysis of: [4] (c) Select the ion in each case, that would get selectively discharged from the aqueous mixture of the ions listed below: Question 4. (b) Write balanced chemical equations to show: [3] (c) Write balanced chemical equations to show how SO3 is converted to Sulphuric acid in the contact process. [2] Question 5. (ii) 11.2 litres of a certain gas at s.t.p. is 24 (b) A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure: [4] (c) Write a balanced chemical equation for the preparation of each of the following salts : [2] Question 6. (b) Identify the term or substance based on the descriptions given below : [4] (c) Give a balanced chemical equation for each of the following: [2] Question 7.
\n(Attempt all questions from this Section)<\/p>\n
\n(a) Fill in the blanks from the choices given in brackets: [5]
\n(i) The energy required to remove an electron from a neutral isolated gaseous atom and convert it into a positively charged gaseous ion is called ………. (electron affinity, ionisation potential, electronegativity)
\n(ii) The compound that does not have a lone pair of electrons is (water, ammonia, carbon tetrachloride)
\n(iii) When a metallic oxide is dissolved in water, the solution formed has a high concentration of ions. (H+<\/sup>, H3<\/sub>O+<\/sup>, OH–<\/sup>)
\n(iv) Potassium sulphite on reacting with hydrochloric acid releases ………….. gas. (Cl2<\/sub>, SO2<\/sub>, H2<\/sub>S)
\n(v) The compound formed when ethene reacts with Hydrogen is ………………………… (CH4<\/sub>, C2<\/sub>H6<\/sub>, C3<\/sub>H8<\/sub>)
\nAnswer:
\n(a) (i) ionisation potential
\n(ii) carbon tetrachloride
\n(iii) OH–<\/sup>
\n(iv) SO2<\/sub>
\n(v) C2<\/sub>H6<\/sub><\/p>\n
\n(i) A chloride which forms a precipitate that is soluble in excess of ammonium hydroxide, is:
\n1. Calcium chloride
\n2. Ferrous chloride
\n3. Ferric chloride
\n4. Copper chloride
\nAnswer:
\n4. Copper chloride<\/p>\n
\n1. alkene
\n2. alkane
\n3. alkyne
\n4. Not a hydrocarbon
\nAnswer:
\n3. alkyne<\/p>\n
\n1. high melting point
\n2. consists of molecules
\n3. always soluble in water
\n4. conducts electricity when it is in the molten state
\nAnswer:
\n2. consists of molecules<\/p>\n
\n1. an acid
\n2. an acid salt
\n3. an alkali
\n4. a salt
\nAnswer:
\n3. an alkali<\/p>\n
\n1. direct combination
\n2. simple displacement
\n3. decomposition
\n4. neutralization
\nAnswer:
\n1. direct combination<\/p>\n
\n(i) Cation that does not form a precipitate with ammonium hydroxide but forms one with sodium hydroxide.
\n(ii) The electrolyte used for electroplating an article with silver.
\n(iii) The particles present in a liquid such as kerosene, that is a non electrolyte.
\n(iv) An organic compound containing – COOH functional group.
\n(v) A solid formed by reaction of two gases, one of which is acidic and the other basic in nature.
\nAnswer:
\n(i) Copper
\n(ii) Sodium argento cyanide
\n(iii) molecules
\n(iv) Carboxylic acid
\n(v) Ammonium chloride<\/p>\n
\n(i) Action of cold and dilute Nitric acid on Copper.
\n(ii) Reaction of Ammonia with heated copper oxide.
\n(iii) Preparation of methane from iodomethane.
\n(iv) Action of concentrated sulphuric acid on Sulphur.
\n(v) Laboratory preparation of ammonia from ammonium chloride.
\nAnswer:
\n(i) 3Cu + 8HNO3<\/sub> \u2192 3CU(NO3<\/sub> )2<\/sub> + 4H2<\/sub>O + 2NO\u2191
\n(ii) 2NH3<\/sub> + 3CuO \u2192 3Cu + 3H2<\/sub>O + N2<\/sub>\u2191
\n(iii) CH3<\/sub>I + 2[H] \u2192 CH4<\/sub> + HI
\n(iv) S + 2H2<\/sub>SO4<\/sub> \u2192 3SO2<\/sub>+ 2H2<\/sub>O
\n(v) 2NH4<\/sub>Cl + Ca(OH)2<\/sub> \u2192 CaCl2<\/sub> + 2H2<\/sub>O + 2NH3<\/sub><\/p>\n
\n(i) Addition of ethyl alcohol to acetic acid in the presence of concentrated Sulphuric acid.
\n(ii) Action of dilute Hydrochloric acid on iron (II) sulphide.
\n(iii) Action of Sodium hydroxide solution on ferrous sulphate solution.
\n(iv) Burning of ammonia in air.
\n(v) Action of concentrated Sulphuric acid on hydrated copper sulphate.
\nAnswer:
\n(i) Fruity smell due to formation of ester is there.
\n(ii) Rotten egg smell due to formation of hydrogen sulphide.
\n(iii) Dirty green precipitates of ferrous hydroxide are formed.
\n(iv) Yellowish green flame is produced when ammonia bums in air.
\n(v) Hydrated copper sulphate which is blue in colour change to anhydrous copper sulphate which is white in<\/p>\n
\n1. 2, 3 – dimethyl butane
\n2. diethyl ether
\n3. propanoic acid
\n(ii) From the list of terms given, choose the most appropriate term to match the given de-scription.
\n(calcination, roasting, pulverisation, smelting)
\n1. Crushing of the ore into a fine powder.
\n2. Heating of the ore in the absence of air to a high temperature.
\nAnswer:
\n1. (i)\u00a0 2, 3 – dimethyl butane
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-1.png\")
\n2. (diethyl ether) C2<\/sub>H5<\/sub> – O – C2<\/sub>H5<\/sub>
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-2.png\")
\n3. propanoic acid CH3<\/sub> – CH2<\/sub> – COOH
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-3.png\")
\n(ii) 1. Pulverisation
\n2. Calcination<\/p>\n
\n(ii) Calculate the percentage of water of crystallization CuSO4<\/sub>.5H2<\/sub>O (H = 1,O = 16, S = 32, Cu = 64)
\n(iii) A compound of X and Y has the empirical formula XY2<\/sub>. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.
\nAnswer:
\n(i) 23 g of sodium \u2192 1 gram atom
\n1 g of sodium \u2192 \\(\\frac{1}{23}\\) gram atom
\n4.6 g of sodium \u2192 = \\(\\frac{1}{23} \\times \\frac{4.6}{10}=\\frac{2}{100}\\) =0.02gatoms<\/p>\n
\n= [64 + 32+4 x 16] + 5[18] – [64 + 32+64] + [90]
\n= 160+90
\n= 250
\n% of water of crystallisation =\\(\\frac{90}{250} \\times 100\\)
\n= 36%<\/p>\n
\nE.F.W. = V.D.
\nM.W. = 2 \u00d7 V.D.
\nM.W. = 2 \u00d7 [E.F.W.]
\nSo molecular formula = (XY2<\/sub>)2<\/sub> = X2<\/sub>Y4<\/sub><\/p>\n
\n(i) A solid non-metal belonging to the third period.
\n(ii) A metal of valency 1.
\n(iii) A gaseous element with valency 2.
\n(iv) An element belonging to Group 2.
\n(v) A rare gas.
\nAnswer:
\n(i) \u2192 15
\n(ii) \u2192 19
\n(iii) \u2192 8
\n(iv) \u2192 4
\n(v) \u2192 2<\/p>\n
\nAttempt my four questions from this Section<\/p>\n
\n(a) Arrange the following as per the instruction given in the brackets:
\n(i) He, Ar, Ne (Increasing order of the number of electron shells)
\n(ii) Na, Li, K (Increasing Ionisation Energy)
\n(iii) F, Cl, Br (Increasing electronegativity)
\n(iv) Na, K, Li (Increasing atomic size)
\nAnswer:
\n(a)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-4.png\")
<\/p>\n
\n(i) Water
\n(ii) Calcium oxide
\nAnswer:
\n(i) Covalent bonding
\n(ii) Ionic bonding<\/p>\n
\n(i) How will you distinguish between Ammonium hydroxide and Sodium hydroxide using copper sulphate solution?
\n(ii) How will you distinguish between dilute hydrochloric acid and dilute sulphuric acid using lead nitrate solution ?
\nAnswer:
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-5.png\")
<\/p>\n
\n(i) On performing the flame test salt P produces a lilac coloured flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in Ammonium hydroxide solution.
\n(ii) When dilute HCl is added to a salt Q, a brisk effervescence is produced and the gas turns lime water milky.
\nWhen NH4<\/sub>OH solution is added to the above mixture (after adding dilute HC1), it produces a white precipitate which is soluble in excess NH4OH solution.
\nAnswer:
\n(i) KCl
\n(ii) ZnCO3<\/sub><\/p>\n
\n(a) Draw an electron dot diagram to show the formation of each of the following compounds: [4]
\n(i) Methane
\n(ii) Magnesium Chloride [H = 1, C = 6, Mg = 12, Cl = 17]
\nAnswer:
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-6.png\")
<\/p>\n
\n(i) fused lead bromide using graphite electrodes.
\n(ii) copper sulphate solution using copper electrodes.
\nAnswer:
\n(i) At anode :
\nDark reddish brown fumes of bromine evolve at the anode.
\nAt cathode:
\nGreyish white metal lead is formed on the cathode.
\n(ii) At anode:
\nAnode decreases in size due to the formation of copper ions.
\nAt cathode:
\nReddish brown copper is deposited<\/p>\n
\n(i) SO42-<\/sup>, NO3<\/sub>–<\/sup>and OH–<\/sup>
\n(ii) Pb2+<\/sup>, Ag+<\/sup> and Cu2+<\/sup>
\nAnswer:
\n(i) OH–<\/sup>
\n(ii) Ag–<\/sup><\/p>\n
\n(a) Certain blank spaces are left in the following table and these are labelled as A, B, C, D and E.
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-7.png\")
\nIdentify each of them. [5]
\nanwer:
\n(a) A \u2192 Below 200\u00b0C(NaHSO4<\/sub>)
\nAbove 200\u00b0C(Na2<\/sub>S04<\/sub>)
\nB \u2192 Upward displacement of air
\nC \u2192 Magnesium nitride (Mg3N2) and water
\nD \u2192 Calcium oxide
\nE \u2192 Downward displacement of air<\/p>\n
\n(i) The oxidizing action of cone. Sulphuric acid on Carbon.
\n(ii) The behaviour of H2<\/sub>SO4<\/sub> as an acid when it reacts with Magnesium.
\n(iii) The dehydrating property of cone. Sulphuric acid with sugar.
\nAnswer:
\n(i) C + 2H2<\/sub>SO4<\/sub> \u2192 2H2<\/sub>O+CO2<\/sub>+2SO2<\/sub>
\n(ii) Mg + H2<\/sub>SO4<\/sub> \u2192 MgSO4<\/sub> + H2<\/sub>\u2191
\n(iii) C12<\/sub>H22<\/sub>O11<\/sub>+H2<\/sub>SO4<\/sub> \u2192 12C + 11H2<\/sub>O<\/p>\n
\nAnswer:
\n(c)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-8.png\")
<\/p>\n
\n(a) (i) Propane bums in air according to the following equation: [4]
\nC3<\/sub>H8<\/sub> + 5O2<\/sub>\u00a0 \u2192 3CO2<\/sub> + 4H2<\/sub>O.
\nWhat volume of propane is consumed on using 1000 cm3<\/sup> of air, considering only 20% of air contains oxygen?
\n(ii) The mass of 11..2 litres of a certain gas at s.t.p. is 24g. Find the gram molecular mass of the gas.
\nAnswer:
\n(i)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-9.png\")
\nIf air is 100, then oxygen is 20%
\nIf air is 100cm3, then oxygen is \\(\\frac{20}{100} \\times 1000\\)= 200 cm3
\nIf 5 vol. of oxygen is used, then propane is 1 vol.
\n1 vol. of oxygen is used, then propane is \\(\\frac{1}{5}\\) vol.
\nIf 200 cm3<\/sup> of oxygen is used, then propane is \\(\\frac{1}{5}\\)<\/p>\n
\n1 litre of a certain gas at s.t.p. is \\(\\frac{24}{11.2}\\)
\n22.4 litres of a certain gas at s.t.p. is \\(\\frac{24}{11.2} \\times 22.4 \\mathrm{L}=48 \\mathrm{g}\\)<\/p>\n
\n(i) Find the number of moles of hydrogen present.
\n(ii) What weight of CO2<\/sub> can the cylinder hold under similar conditions of temperature and pressure? (H= 1, C = 12,O -16)
\n(iii) If the number of molecules of hydrogen in the cylinder is X, calculate the number of CO2\u00a0<\/sub>molecules in the cylinder under the same conditions of temperature and pressure.
\n(iv) State the law that helped you to arrive at the above result.
\nAnswer:
\n(i) Weight of hydrogen = 2 \u00d7 1 g = 2 g
\n2 g of hydrogen corresponds to 1 mole of hydrogen
\n1 g of hydrogen corresponds to \\(\\frac{1}{2}\\) mole of hydrogen
\n1000 g of hydrogen corresponds to \\(\\frac{1}{2}\\) \u00d7 1000 g mole of H2<\/sub> = 500 moles
\n(ii) 1 mole of H2<\/sub> occupy 22.4 L
\n500 mole of H2<\/sub> occupy = 22.4 x 500
\nBy Avogadro\u2019s law the volume occupied by CO2<\/sub> will be same
\nWeight of CO2<\/sub> = 12 + 2 x 16 = 44 g
\n22.4 L will weigh 44
\n1L will weigh \\(\\frac{44}{22.4}\\)
\n22.4 x 500L will weigh \\(\\frac{44}{22.4} \\times 22.4 \\times 500=22000 \\mathrm{g}=22 \\mathrm{kg}\\)
\n(iii) X (Because of Avogadro\u2019s law)
\n(iv) Avogadro\u2019s law<\/p>\n
\n(i) Copper carbonate
\n(ii) Ammonium sulphate crystals
\nAnswer:
\n(i) CU(NO3<\/sub>)2\u00a0<\/sub>+ Na2<\/sub>CO3<\/sub> \u2192 CuCO3<\/sub> + 2NaNO3<\/sub>
\n(ii) 2NH4<\/sub>Cl + H2SO4 \u2192 (NH4<\/sub>)2 SO4<\/sub> + 2HCl<\/p>\n
\n(a) Give a balanced chemical equation for each of the following: [4]
\n(i) Action of cone. Nitric acid on Sulphur.
\n(ii) Catalytic oxidation of Ammonia.
\n(iii) Laboratory preparation of Nitric acid.
\n(iv) Reaction of Ammonia with Nitric acid.
\nAnswer:
\n(i) S + 6HNO3<\/sub> \u2192 H2<\/sub>SO4\u00a0<\/sub>+ 6NO2\u00a0<\/sub>+ 2H2<\/sub>O
\n(ii)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-10.png\")
\n(iii)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-11.png\")
\n(iv) NH3<\/sub>\u00a0+\u00a0HNO3\u00a0<\/sub>\u2192\u00a0NH4<\/sub>NO3<\/sub><\/p>\n
\n(i) Ice like crystals formed on cooling an organic acid sufficiently.
\n(ii) Hydrocarbon containing a triple bond used for welding purposes.
\n(iii) The property by virtue of which the compound has the same molecular formula but different structural formulae.
\n(iv) The compound formed where two alkyl groups are linked by imageee group.
\nAnswer:
\n(i) Acetic acid
\n(ii) Acetylene
\n(iii) Isomers
\n(iv) Ketone<\/p>\n
\n(i) Preparation of ethane from Sodium propionate .
\n(ii) Action of alcoholic KOH on bromoethane.
\nAnswer:
\n(i)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-12.png\")
\n(ii)
\n![\"ICSE](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2019\/10\/ICSE-Chemistry-Question-Paper-2017-Solved-for-Class-10-13.png\")
<\/p>\n
\n(a) Name the following: [4]
\n(i) The process of coating of iron with zinc.
\n(ii) An alloy of lead and tin that is used in electrical circuits.
\n(iii) An ore of zinc containing its sulphide.
\n(iv) A metal oxide that can be reduced by hydrogen.
\nAnswer:
\n(i) Galvanisation
\n(ii) Solder
\n(iii) Zinc blende
\n(iv) Copper oxide<\/p>\n