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GOLDCREST HIGH-LATUR ON THE WINGS OF EXCELLENCE PRELIM-02 SUBJECT:-CHEMISTRY TIME: 2 HOURS DATE:- GRADE-10 MARKS:80 General Instructions 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 the paper is the time allotted for writing the answers. Attempt all questions from Section I and any four questions from Section II. The intended marks of questions or parts of questions are given in brackets [ ]. SECTION-I(40 Marks) Question-01 (a) Select correct answer from A, B, C and D write only the letter corresponds to correct answer : [10] (i) The basicity of acetic acid is a) 1 b) 2 c) 3 d) 4 (ii) A salt prepared by simple displacement reaction, i.e. action of dil acid on metal is a) PbCl 2 b) CuCl2 c) AgCl3 d) HgCl (iii) A covalent compound which in aqueous state conduct electricity. a) CCl 4 b) CS2 c) NH3 d) C2H4 (iv) A metal whose hydroxide does not decompose on heating but its nitrate decompose is a) Calcium b) Aluminium c) Sodium d) Iron. (v) The oxidized product obtained on reaction of H2S gas with dil HNO is .. a) Sulphur dioxide b) Sulphur c) Sulphuric acid d) Sulphurous acid (vi) Metals lose electrons during ionization. This change is called a) Oxidation b) Reduction c) Redox d) Displacement (vii) The aqueous solution of the compound which contains both ions and molecules. a)Sulphuric acid b) Hydrochloric acid c) Nitric acid d) Acetic acid (viii) Ethyne gas when pass through ammonical cuprous chloride. It produce :a) White precipitate b) Red precipitate (c) Dirty green precipitate d)Reddish brown precipitate (ix) Number of hydrogen atom present is acetic acid. a) 2 b) 3 c) 4 d) 5 (x) The gas law which relates the volume of gas to the number of molecules of the gas is a) Avogadro s law b) Gay Lussac s law c) Boyle s law d) Charle s law (b) How will you distinguish each of the following compound by a chemical test : [5] i) Sodium Sulphate and Sodium Sulphide ii) Copper hydroxide and Lead hydroxide iii) Acetylene and ethylene iv) Ferrous sulphate and Ferric sulphate v) Nitric acid and sulphuric acid (c) Name the method used to prepare the following salts : i) Lead sulphate iii) Iron (II) chloride [5] ii) Soduim chloride iv) Zinc sulphate v) Copper chloride (d) Give appropriate scientific reasons for the following statements: [5] i)Zinc oxide can be reduced to zinc by using carbon monoxide,but aluminium oxide can not be reduced by a reducing agent (ii) Carbon tetrachloride does not conduct electricity. (iii)During electrolysis of molten lead bromide graphite anode is preferred to other electrodes, (iv) The electrical conductivity of acetic acid is less in comparison to the electrical conductivity of dilute sulphuric acid (v) Electolysis of molten lead bromide is considered to be a redox reaction (e) State the IUPAC name of the following: i) iv) ii) [5] iii) v) (f) Distinguish between the following with respect to the characteristic stated: Distinguish Between i) Sodium atom and Sodium ion ii) Calcination and Roasting iii) Copper cation and Calcium cation iv) Hygroscopic and Deliquescent substances v) Conductors and Electrolytes [5] Characteristic Reaction with water Example of an ore Flame test Definition Carriers of Electric current. (g) Solve: [5] 400 c.c. of butane is burnt with 3000 c.c. of oxygen Find i) the amount of carbon dioxide formed and unused oxygen ii) ii) If 4 moles of butane is used, than find the number of moles of carbon dioxide formed. iii) Also find the number of molecules of carbon dioxide present at the same time iv) If 2 moles of butane is used, find the volume of carbon dioxide formed (Atomic Weight of C=12,O=16,H=1) SECTION-II(40 MARKS) (Attempt any four questions from this section) Question-02 (a)Identify the gas evolved and give the chemical test in each of the following cases: (i)Dilute hydrochloric acid reacts with sodium sulphite. (ii) Dilute hydrochloric acid reacts with iron(II) sulphide. [2] (b)State your observations when ammonium hydroxide soln. is added drop by drop and then in excess to each of the following solutions: (i) Copper sulphate solution (ii) Zinc sulphate solution. [2] (c) Write equations for the reactions taking place at the two electrodes(mentioning clearly the name of the electrode) during the electrolysis of : (i) Acidified copper sulphate solution with copper electrodes. (ii) Molten lead bromide with inert electrodes. (iii) Electrolysis of acidified water using platinum electrodes. [4] (d) Compare the properties of covalent and electrovalent compounds on the following Points : i) Solubility ii) Conductivity [2] Question-03 (a) The following questions refer to the periodic table: [5] i) Name the second element of the period 3. ii) Name the element which has the highest ionization potential in period 2. iii) Name the element which shows the property of catenation. iv) Name a metalloid in Period 2. v) Name the element that does not form an oxide in period 1. (b) Answer the following questions based on the diagram below : [3] i) Name the experiment ii) Name the solution A and the gas B. (iii)What conclusion can be drawn from this experiment (c) (i)Draw a diagram to show the arrangement used for the absorption of HCl in water. (ii)Why such a arrangement is necessary ? [2] Question-04 (a)(i)Write the equation for the reaction where the aluminium oxide is formed for the electrolytic extraction of aluminium which is obtained by heating aluminium hydroxide. [1] (ii) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis (b) [2] Study the following reaction scheme and answer the following questions: (i) Identify the substances A to F by giving their name and chemical formula . (ii)Why this catalyst G is preferred over other catalyst? (iii)Write the equation for the conversion of sulphur dioxide to sulphur trioxide.? [3] (iv)Why SO3 is not dissolved in water to get Sulphuric acid? (v)In which way conc.Sulfuric acid is reacting with sucrose? [4] Question-05 (a) How do you obtain: i) Carbon from Ethyne ii) Ethyne from 1, 2 dibromethane iii) Sodium Ethoxide from sodium iv) Vinegar from Ethanol v) Methane from sodium acetate [5] (b) i) What is glacial acetic acid? [2] ii) What is denatured alcohol? (c) Calculate the number of moles present in : i) 20 gm of calcium carbonate ii) 2 1023 molecules of carbon monoxide. (Ca = 40, C = 12, O = 16). iii) Calculate the vapour density and molecular mass of Carbon dioxide if 200ml of gas at S.T.P Weighs 0.40g. [Given 1L of H2 at S.T.P. weighs 0.09g] [3] Question-06 (a) Identity the substances P, Q, R, S and T in each case based on the information given below: i) The deliquescent salt P, turns yellow on dissolving in water and gives a reddish brown precipitate with sodium hydroxide solution. ii) The white crystalline solid Q is soluble in water. It liberates a pungent smelling gas when heated with sodium hydroxide solution. iii) The pale green solid R turns reddish brown on heating. Its aqueous solution gives a white precipitate with barium chloride. iv) The reddish brown liquid S is dissolved in water. When ethyne gas is passed through it, it turns colourless. v) The nitrate T does not leave any residue on heating. [5] (b) i) Write the balanced equation for the laboratory preparation of Ammonia from Ammonium chloride and slaked lime. ii) How is Ammonia dried and collected in the lab? iii) How is high solubility of Ammonia demonstrated? iv) What do you observe when Ammonia solution is added to aqueous solution of Copper Sulphate? Write balanced equation also. [5] Question-07 (a)Give the structural formula for each of the following: i) 2,2-Dimethylbutanal. ii)3-Chloropropanoic acid iii) 2-Methylbut-2-ene [3] (b)What do you mean by preferential or selective discharge of ions at electrode. What are the factors affecting it? [3] (c) Define : i)Avogadro s law ii)Polar covalent compound iii) Co-ordinate bond iv) Spectator Ion [4] ________________________________ END ________________________________
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