ICSE BOARD PAPER-2017-CHEMISTRY

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  • Q1

    (a) Fill in the blanks from the choices given in brackets:

    (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)

    (ii) The compound that does not have a lone pair of electrons is __________. (water, ammonia, carbon tetra chloride)

    (iii) When a metallic oxide is dissolved in water, the solution formed has a high concentration of __________ ions. (H+, H3O,OH)

    (iv) Potassiumsulphite on reacting with hydrochloric acid releases _________ gas. (Cl2, SO2, H2S)

    (v) The compound formed when ethene reacts with Hydrogen is __________. (CH4, C2H6, C3H8)

     

    (b) Choose the correct answer from the option given below:

    (i) A chloride which forms a precipitate that is soluble in excess of ammonium hydroxide, is:

    1. Calcium chloride

    2. Ferrous chloride

    3. Ferric chloride

    4. Copper chloride

     

    (ii)If the molecular formula of an organic compound is C10H18 it is:

    1.alkene

    2.alkane

    3.alkyne

    4. Not a hydrocarbon

    (iii)Which of the following is a common characteristic of a covalent compound?

    1. high melting point

    2. consists of molecules

    3. always soluble in water

    4. conducts electricity when it is in the molten state

     

    (iv) To increase the pH value of a neutral solution, we should add:

    1.an acid

    2.an acid salt

    3.an alkali

    4.a salt

     

    (v) Anhydrous iron (III) chloride is prepared by:

    1.direct combination

    2.simple displacement

    3.decomposition

    4.neutralization

     

    (c)Identify the substance underlined, in each of the following cases:

    (i) Cation that does not form a precipitate with ammonium hydroxide but forms one with sodium hydroxide.

    (ii)The electrolyte used for electroplating an article with silver.

    (iii)The particles present in a liquid such as kerosene, that is a non-electrolyte.

    (iv)An organic compound containing –COOH functional group.

    (v)A solid formed by reaction of two gases, one of which is acidic and the other, basic in nature.

     

    (d) Write a balanced chemical equation for each of the following:

    (i) Action of cold and dilute Nitric acid on Copper.

    (ii) Reaction of Ammonia with heated copper oxide.

    (iii) Preparation of methane from iodomethane.

    (iv) Action of concentrated sulphuric acid on Sulphur.

    (v) Laboratory preparation of ammonia from ammonium chloride.

     

    (e) State one relevant observationfor each of the following reactions:

    (i) Additionof ethyl alcohol to acetic acid in the presence of concentratedSulphuric acid.

    (ii) Action of dilute Hydrochloric acid on iron (II) sulphide.

    (iii) Action of Sodium hydroxide solution on ferrous sulphate solution.

    (iv) Burning of ammonia in air.

    (v) Action of concentrated Sulphuric acid on hydrated copper sulphate.

     

    (f)(i)Draw the structural formula for each of the following:                              

    1. 2,3-dimethyl butane

    2. diethyl ether

    3. propanoic acid

    (ii) From the list of terms given, choose the most appropriate term to match the given description.

    (calcination, roasting, pulverization, smelting)

    1. Crushing of ore into a fine powder.

    2.Heating of the ore in the absence of air to a high temperature.

     

    (g) (i)Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23).

    (ii) Calculate the percentage of water of crystallization in CuSO4.5H2O

    (H = 1, O = 16, S =32, Cu = 64)

    (iii)A compound of X and Y has the empirical formula XY2. Its vapour density is equal to its empirical formula weight. Determine its molecular formula.

    (h) Match the atomic number 2, 4, 8, 15 and 19 with each of the following:

    (i) A solid non-metal belonging to the third period.

    (ii) A metal of valency 1.

    (iii) A gaseous element with valency 2.

    (iv) An element belonging to Group 2.

    (v)A rare gas.

    Marks:40
    Answer:

    (a)

    (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 ionisation potential.

    (ii) The compound that does not have a lone pair of electrons is carbon tetra chloride.

    (iii) When a metallic oxide is dissolved in water, the solution formed has a high concentration of OH ions.

    (iv) Potassium sulphite on reacting with hydrochloric acid releases SO2 gas.

    (v) The compound formed when ethene reacts with Hydrogen is C2H6.

     

    (b)

    (i) 4–Copper chloride

    Explanation:Copper chloride reacts with ammonium hydroxide to form pale blue precipitate of copper hydroxide which dissolves in excess ammonium hydroxide solution to give deep blue coloured solution.

    (ii) 3–Alkyne

    Explanation: Alkynes are represented by general formulae CnH2n-2.

    In C10H18, n=2

    C10H2×10 –2= C10H18

    Hence, the given compound is an alkyne.

    (iii) 2–consists of molecules

    Explanation:Covalent compounds are formed by mutual sharing of electrons between atoms to form molecules. So, covalent compounds consist of only molecules.

    (iv) 3– an alkali

    Explanation:pH of a neutral solution is 7. If pH of solution is above 7 it is basic and below 7 is acidic. So, in order to increase the pH above 7, an alkali is added to it.

    (v) 1–direct combination

    Explanation:Iron(III) chloride(FeCl3) is formed by direct combination of iron with Cl2.

    (c)

    (i) Ca2+

    (ii) Sodium argentocyanide

    (iii) Molecules

    (iv) CH3COOH (Acetic acid)

    (v) NH4Cl (Ammonium chloride)

     

    (d)

    (e)

    (i) Sweet smelling ester (ethyl ethanoate) is formed when ethyl alcohol is added to acetic acid in the presence of concentrated sulphuric acid.

    (ii)Iron(II) sulfide reacts with hydrochloric acid to form ferrous sulfate and hydrogen sulfide(H2S) gas.H2S smells like rotten egg.

    (iii) When sodium hydroxide solution reacts with ferrous sulphate solution, dirty green precipitate of ferrous hydroxide, Fe(OH)2 is formed which is insoluble in excess ammonium hydroxide solution.

    (iv)When ammonia burns in air to form nitric oxide and water.

    (v) Hydrated copper sulfate is blue in colour. When concentrated sulfuric acid is added to it, hydrated copper sulfate turns white in colour because it loses water of crystallization.

     

    (f)

    (i)

    1. 2,3–dimethyl butane

    2. Diethyl ether

    3. Propanoic acid

    (ii)

    1.Pulverisation

    2. Calcination

    (g)

    (i)



    (ii)

    (iii)

    (h)

    (i) Atomic number– 15 (Phosphorus)

    (ii) Atomic number– 19 (Potassium)

    (iii) Atomic number– 8 (Oxygen)

    (iv) Atomic number–4 (Beryllium)

    (v) Atomic number– 2 (Helium)

    View Answer
  • Q2

    (a) Arrange the following as per the instruction given in the brackets:

    (i) He, Ar, Ne (Increasing order of the number of electron shells)

    (ii) Na, Li, K (Increasing Ionisation Energy)

    (iii) F, Cl, Br (Increasing electronegativity)

    (iv)Na, K, Li (Increasing atomic size)

    (b) State the type of Bonding in the following molecules:                                             

    (i)Water

    (ii) Calcium oxide

    (c) Answer the following questions:

    (i) How will you distinguish between Ammonium hydroxide and Sodium hydroxide using copper sulphate solution?

    (ii) How will you distinguish between dilute hydrochloric acid and dilute sulphuric acid using lead nitrate solution?

    (d) Identify the salts P and Q from the observation given below:

    (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.

    (ii) When dilute HCl is added to a salt Q, a brisk effervescence is produced and the gas turns lime water milky.

    When NH4OH solution is added to the above mixture (after adding dilute HCl), it produces a white precipitate which is soluble in excess NH4OH solution.

    Marks:10
    Answer:

    (a)

    (i) Increasing order of number of shells: He < Ne

    (ii) Increasing order of Ionisation Energy: K < Na < Li

    (iii) Increasing order of Electro negativity: Br

    (iv) Increasing order of Atomic size : Li < Na < K

    (b)

    (i) Water– Covalent bond

    (ii) Calcium oxide– Ionic bond

    (c)

    (i)Ammonium Hydroxide –When Ammonium hydroxide solution is added to copper sulphate solution, pale blue precipitate of Cu(OH)2 is formed which further does not dissolve in excess ammonium hydroxide.

    Sodium Hydroxide –When sodium hydroxide solution is added to copper sulphate solution, pale blue precipitate of Cu(OH)2 is formed which further dissolves in excess sodium hydroxide to form Prussian blue coloured solution.

    (ii)

    Dilute Hydrochloric acid

    Dilute Sulphuric acid

    When dilute hydrochloric acid is added to lead nitrate solution, lead chloride is formed.

     

    When dilute sulphuric acid is added to lead nitrate solution, lead sulphate is formed.

     

     

     

     

     

    (d)

    (i)salt P – KCl

    Explanation- Salt P gives lilac colour to the flame which indicates that it contains potassium ion (K+). Further its solution produces white precipitate with silver nitrate solution which indicates the presence of Cl which is further confirmed by dissolving it in ammonium hydroxide solution.

    (ii)salt Q – ZnCO3

    Explanation-When dilute HClis added to ZnCO3, brisk effervescence of CO2 is produced which turns lime water milky.

    It confirms the presence of CO3.

    Further when ammonium hydroxide is added to the above mixture containing zinc chloride, white precipitate of Zn(OH)2 is produced which is soluble in excess NH4OH.

    This confirms the presence of Zn2+.

    View Answer
  • Q3

    (a) Draw an electron dot structure diagram to show the formation of each of the following compounds:

    (i) Methane

    (ii) Magnesium Chloride

    [H = 1, C = 6, Mg = 12, Cl = 17]             

    (b) State the observation at the anode and at the cathode during the electrolysis of:           

    (i) fused lead bromide using graphite electrodes.

    (ii) copper sulphate solution using copper electrodes.                                                 

    (c) Select the ion in each case, that would get selectively discharged from the aqueous mixture of the ions listed below:

    (i) SO42-, NO3 and OH

    (ii) Pb2+, Ag+ and Cu2+

    Marks:10
    Answer:

    (a)

    (i) Formation of Methane

    (ii) Formation of Magnesium Chloride

    (b)

    (c)

    (i) OH-

    Explanation–among SO42-, NO3 and OH, OH has maximum ease of oxidation. So, it gets selectively discharged first at anode.

    (ii) Ag+

    Explanation– Ag+ lies at lower side of electrochemical series of metal and has maximum ease of reduction.

    View Answer
  • Q4

    (a) Certain blank spaces are left in the following table and these are labelled as A, B, C, D and E. Identify each of them.                       

    S.No.

    Lab preparation of

    Reactant used

    Products formed

    Drying agent

    Methods of collection

    (i)

    HCl gas

    NaCl + H2SO4

    __A__

    conc. H2SO4

    __B__

    (ii)

    NH3 gas

    ___C___

    Mg(OH)2

    NH3

    __D__

    __E__

     

    (b) Write balanced chemical equation to show:

    (i) The oxidizing action of conc. Sulphuric acid on Carbon.

    (ii) The behavior of H2SO4 as an acid when it reacts with Magnesium.

    (iii) The dehydrating property of conc. Sulphuric acid with sugar.

    (c) Write balanced chemical equation to show how SO3 is converted to Sulphuric acid in the contact process. 

    Marks:10
    Answer:

    (a)

    S.No.

    Lab preparation of

    Reactant used

    Products formed

    Drying agent

    Methods of collection

    (i)

    HCl gas

    NaCl + H2SO4

    NaHSO4 + HCl

    conc. H2SO4

    Downward displacement of air

    (ii)

    NH3 gas

    Mg3N2 + H2O

     

    Mg(OH)2

    NH3

    Calcium oxide( Quicklime)

    Downward displacement of air

     

    (b)

    (c)

    View Answer
  • Q5

    (a) (i) Propane burns in air according to the following equation:

    C3H8 + 5O2 3CO2 + 4H2O

    What volume of propane is consumed on using 1000 cm3 of air, considering only 20% of air contains oxygen?

    (ii) The mass of 11.2 litres of a certain gas at s.t.p. is 24 g. Find the gram molecular mass of the gas.

    (b) A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure:

    (i) Find the number of moles of hydrogen present.

    (ii) What weight of CO2 can the cylinder hold under similar conditions of temperature and pressure? (H=1, C=12, O=16)

    (iii) If the number of molecule of hydrogen in the cylinder is X, calculate the number of CO2 molecules in the cylinder under the same conditions of temperature and pressure.

    (iv) State the law that helped you to arrive at the above result.

    (c) Write a balanced chemical equation for the preparation of each of the following salts:

    (i) Copper carbonate

    (ii) Ammonium sulphate crystals

    Marks:10
    Answer:

    (a)

    (b)

    (c)

    View Answer
  • Q6

    (a) Give a balanced chemical equation for each of the following:                                      

    (i) Action of conc. Nitric acid on Sulphur.

    (ii) Catalytic oxidation of Ammonia.

    (iii) Laboratory preparation of Nitric acid.

    (iv) Reaction of Ammonia with Nitric acid.

    (b) Identify the term or substance based on the description given below:                      

    (i) Ice like crystals formed on cooling an organic acid sufficiently.

    (ii) Hydrocarbon containing a triple bond used for welding purposes.

    (iii) The property by virtue of which the compound has the same molecular formula but different structural formulae.

    (iv) The compound formed where two alkyl groups

    are linked by  group.

    (c) Give a balanced chemical equation for each of the following:                                         

    (i) Preparation of ethane from Sodium propionate.

    (ii) Action of alcoholic KOH on bromoethane.

    Marks:10
    Answer:

    (a)

    (b)

    (i) Glacial acetic acid

    (ii)Ethyne (Acetylene)

    (iii) Isomerism

    (iv) Ketone

    (c)

     

    View Answer
  • Q7

    (a) Name the following:                      

    (i) The process of coating of iron with zinc.

    (ii) An alloy of lead and tin that is used in electrical circuits.

    (iii) An ore of zinc containing its sulphide.

    (iv) A metal oxide that can be reduced by hydrogen.

    (b) Answer the following questions with respect to the electrolytic process in the extraction of aluminium:                                            

    (i) Identify the components of the electrolyte other than pure alumina and the role played by each.

    (ii) Explain why powdered coke is sprinkled over the electrolytic mixture.

    (c) Complete the following by selecting the correct option from the choice given:

    (i) The metal which does not react with water or dilute H2SO4 but reacts with concentrated H2SO4 is _______(Al/Cu/Zn/Fe).

    (ii) The metal whose oxide, which is amphoteric is reduced to metal by carbon reduction ______.(Fe/Mg/Pb/Al)

    (iii) The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is ______.(Al/Na/Mg/K)

    Marks:10
    Answer:

    (a)

    1. Galvanisation
    2. Solder
    3. Zinc blende (ZnS)
    4. Copper oxide

    (b)

    (i) Components of the electrolyte in Electrolytic process in extraction of Aluminium are:

    Cryolite (Na3AlF6) –It is added to lower the fusion temperature in the electrolytic process.

    Fluorspar (CaF2)– It acts as solvent for the electrolytic mixture.

    (ii) Powdered coke is sprinkled over the electrolytic mixture due to two reasons:

    1. In order to reduce heat loss by radiation.
    2. To prevent burning of anode

    (c)

    (i) The metal which does not react with water or dilute H2SO4 but reacts with concentrated H2SO4 is Cu (Al/Cu/Zn/Fe).

    (ii) The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction Pb. (Fe/Mg/Pb/Al)

    (iii) The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is Mg. (Al/Na/Mg/K)

    View Answer