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SAINT MILAREPA SCHOOL CHEMISTRY SCIENCE Paper 2 (Two hours) Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during the first 15 minutes. This time is to be spent in reading the Question Paper. The time given at the head of this paper is the time allowed for writing the answers. Section I is compulsory. Attempt any four questions from Section II. The intended marks for questions or parts of questions are given in brackets [ ]. SECTION I (40 Marks) Attempt all questions from this Section Question 1 (a) Choose the most appropriate answer. (i) Which of the following is a common characteristic of a covalent compound? A High melting point. B Conducts electricity when it is in the molten state. C Consists of molecules. D Always soluble in water. (ii) To increase the pH value of a neutral solution, we should add: A An acid B An acid salt C An alkali D A salt (iii) A salt which in solution gives a bluish white precipitate with NaOH solution and a white precipitate with BaCl2 solution is: A CuSO4 B FeSO4 C Fe2 (SO4)3 D CuCl2 (iv) The gas law which relates the volume of a gas to moles of the gas is: A Avogadro s Law B Gay-Lussac s Law C Boyle s Law D Charle s Law (v) During the electrolysis of acidified water which of the following takes place: A Oxygen is released at cathode. B Oxygen is released at anode. C Hydrogen is released at anode. D Sulphur dioxide is released at anode. (vi) Duralumin is an alloy of A Al and Cu B Cu and Sn C Al and Ag D Al and Fe (vii) Hydrogen chloride can be obtained by adding concentrated Sulphuric acid to: A NaCl B Na2SO4 C Na2CO3 D NaNO3. (viii) A compound which liberates reddish brown gas around the anode during electrolysis in its molten state is: A. Sodium chloride B Copper (II) oxide C Copper (II) sulphate D Lead (II) bromide (ix) Anhydrous iron ( III) chloride is prepared by: A Direct combination B Simple displacement C Decomposition 72 ICSE Specimen Question Paper D Neutralisation (x) The element with the highest ionization potential in the periodic table is: A He B Ne C Ar D Xe [10] (b) The equation for the action of heat on calcium nitrate is: 2Ca(NO3)2 2CaO + 4 NO2 + O2 (i) How many moles of NO2 are produced when 1 mole of Ca(NO3)2 decomposes? (ii) What volume of O2 at S.T.P. will be produced on heating 65.6 g of Ca (NO3)2? (iii) Find out the mass of CaO formed when 65.6 g of Ca(NO3)2 is heated. (iv) Find out the mass of Ca(NO3)2, required to produce 5 moles of gaseous products. (v) Find out the mass of Ca(NO3)2 required to produce 44. 8 L of NO2 at S.T.P. (vi). Relative molecular mass of Ca(NO3)2 = 164 and of CaO = 56) (c) Complete the following equations: (i) (ii) AlC l 3 + NaOH CuC O 3 (iii) Pb C O +HN O 3 3 (iv) MgO + HCl (v) Zn (s) + Cu S O 4 (5) (d) Identify the following substances: (i) An acidic gas which gives dense white fumes with NH3. (ii) An alkane which can also be called a green house gas. (iii) A solid which when kept in the open, forms a solution after sometime. (iv) An alloy used in electrical fittings. 73 ICSE Specimen Question Paper (v) (e) A metal which gives hydrogen gas on reacting with both dilute acid and alkali. [5] Write equations for the following reactions: (i) Magnesium and steam. (ii) Zinc and dilute sulphuric acid. (iii) Zinc and copper sulphate solution. (iv) Concentrated sulphuric acid and sodium hydroxide. (v) (f) Copper carbonate and dil. Sulphuric acid. [5] Name the following: (i) One metal and one non metal which exist in the liquid state at room temperature. (ii) One metallic element more reactive than hydrogen. (iii) The allotrope of the non- metal carbon which conduct electricity. (iv)One ore of an iron. (v) One ore of zinc. (g) Match the following: 1. Ion a. An electrode at which reduction occurs b. An aqueous solution or molten liquid that contains free ions. c. An electrode at which oxidation occurs d. An atom or group of atoms carrying positive or negative charge e. Loss of electrons 2. Anode 3. Oxidation 4. Electrolyte 5. Cathode SECTION II (40 MARKS) Attempt any of the four questions. Question 2. (a) The following questions refer to the periodic table: (i) Name the second last element of the period 3. (ii) How many elements are in the second period? (iii) Name the element which has the highest electron affinity. (iv) Name the element which has the highest electro negativity. (v) Name the element which may be placed on group 1 but is not a metal. [5] 74 ICSE Specimen Question Paper (b) Fill in the blanks using the correct options: (i) Metals have ------ ionisation potential. (low/ high) (ii) Group 18 elements have ------ valence electrons (4 / 8) with the exception of ---- ( He / Ne) with -------- electrons (2 / 8) in valence shell. (iii) Group 2 elements are called ----- metals (alkali / alkaline earth). [5] Question 3. (a) Draw different isomers having the following molecular formula: (i) C5H12 (chain) (ii) C4H8 (position). [5] (b) What is denatured alcohol? (c) Give two important uses of ethanol. (d) Write equations for: (i) Preparation of ethanol by hydration of C2H4. (ii) Preparation of acetic acid from ethanol. [1] [2] [2] Question. 4 (a) Name the method by which following compounds can be prepared: Select the appropriate method from the following list Neutralization; direct combination; precipitation; metal + acid use a method only once. (i) Sodium sulphate (ii) Silver chloride (iii) Iron sulphide. (b) [3] How will you distinguish between following pairs of compounds using NH4OH. (i) Copper sulphate and iron(II) sulphate. (ii) Zinc nitrate and lead nitrate. (iii) Iron(II) sulphate and iron(III) sulphate. [3] (c) Name: (i) A greenish yellow gas with pungent smell. (ii) An oxide which is yellow when hot and white when cold. (iii) A chemical used to deplete ozone layer. 75 ICSE Specimen Question Paper (iv) A crystalline salt without water of crystallization. [4] Question. 5 (a) Name one: (i) metal liquid at room temperature. (ii) non-metal which is a conductor of electricity. (iii) neutral oxide. (iv) metallic oxide which cannot be reduced by hydrogen. (v) (b) non-metal which has lustre. (i) (ii) [5] Name the chief ore of aluminium. Name the process used to concentrate the above mentioned ore. (iii) Why is alumina added to cryolite in the electrolytic reduction of aluminium? (iv) Give cathode and anode reactions involved in extraction of aluminium from its above mentioned ore. (v) Name the process used for the concentration of zinc blende. [5] Question 6. (a) Draw a neat and well labelled diagram for the silver plating on an iron spoon. (b) [3] Copy and complete the following table related to electrolysis. S.No. Name of Electrolyte Name of Cathode Name of Anode 1. CuSO4 (aq.) Copper Copper 2. PbBr2 (molten) Platinum Platinum Product at Cathode Product at Anode [4] (c) Classify the following as oxidation and reduction reaction, also complete the reaction. Cu2+ (i) Cu (ii) Fe3+ Fe2+ (iii) Cl- Cl [3] Question. 7 (a) A compound has the following percentage composition by mass: 76 ICSE Specimen Question Paper Carbon 54.55%, Hydrogen 9.09% and Oxygen 36.26%. Its vapour density is 44. Find the Empirical and Molecular formula of the compound. (H = 1; C = 12; O = 16) (b) Give the electron dot structure of the following: (i) NH3 (ii) CH4 (iii) H3O+ [3] (c) [5] Compare the properties of covalent and electrovalent compounds on the following points: (i) Solubility (ii) Structure. [2] 77 ICSE Specimen Question Paper
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