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THE BISHOP S CO-ED SCHOOL, KALYANI NAGAR, PUNE PRELIMINARY (2) EXAMINATION (2015-2016) SUBJECT: CHEMISTRY CLASS : X (10) READING TIME : 15 MINS TOTAL MARKS : 80 WRITING TIME : 2 HOURS TOTAL NO. OF PAGES : 4 ------------------------------------------------------------------------------------------------------------------------------------------------ -----------------------Section I is compulsory. Attempt any 4 questions from Section II. The intended marks for questions or parts of questions are given in brackets [ ]. All chemical equations must be balanced. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Section I (40 marks) Attempt all the questions from this section. Question 1. a. Select the correct answer from the options given below. i. An element is period 3 whose electron affinity is zero (A) Neon (B) Sulphur (C) Sodium (D) Argon ii. If empirical formula of an organic compound is CH2O then it s molecular formula can be (A) C2H2O2 (B) C2H4O2 (C) C3H6O (D) C6H12O6 iii. Dilute sulphuric acid will produce a white precipitate when added to a solution of (A) Lead Nitrate (B) Zinc Nitrate (C) Copper Nitrate (D) Sodium Nitrate iv. The pH of a solution which reacts with ammonium chloride to liberate ammonia is (A) 7 (B) more than 7 (C) less than 7 (D) less than 3 v. The metal zinc and tin are present in the alloy (A) Bell Metal (B) Brass (C) Bronze (D) German Silver vi. An ore that is calcinated ? (A) PbO (B) ZnS (C) ZnCO3 (D) Fe2O3 vii. Which of the following has smaller size ? (A) Al (B) Al+ (C) Al2+ (D) Al3+ viii. Hydroxide of this metal is soluble in sodium hydroxide solution (A) Magnesium (B) Lead (C) Copper (D) Silver ix. The metallic electrode which does not take part in an electrolytic reaction (A) Cu (B) Ag (C) Pt (C) Ni x. Hydrogen Chloride gas being highly soluble in water is dried by (A) Anhydrous Calcium Chloride (B) Phosphorous Pentoxide (C) Quick Lime (D) Conc. Suphuric Acid b. Name the following [Formula NOT acceptable]. i. The anion present in the salt solution that reacts with barium chloride to form white precipitate insoluble in hydrochloric acid. ii. Two acidic gases that bleach, one colourless and the other coloured. iii. The anion present in the salt solution that reacts with dil. Sulphuric acid to give a gas with brisk effervescence that has no effect on acidified potassium dichromate solution. iv. An acidic gas that can be oxidized to sulphur and which turns acidified potassium permanganate solution from pink to colourless. v. A basic gas that turns Nessler s reagent brown. c. Complete the reactions and mention the property exhibited by the underlined compounds. i. PbO + NaOH ii. S + H2SO4 iii. NH3 + PbO iv. CuO + HNO3 v. PbO2 + HCl d. Match the following. [10] [5] [5] [5] i. ii. iii. iv. v. Salt Zinc Sulphate Ferrous Sulphide Barium Sulphate Ferric Sulphate Sodium Sulphate A. B. C. D. E. Method of preparation Precipitation Oxidation Displacement Neutralization Synthesis e. State the observation for each of the following. [5] i. Zinc nitrate is heated. ii. Excess of chlorine gas is reacted with ammonia. iii. Conc. Sulphuric Acid is added drop wise to crystals of hydrated copper sulphate iv. Excess of ammonia solution is added to zinc and lead salt solution . v. Methyl orange is added to hydrochloric acid. f. The equation for burning of ethane is: 2C2H2 + 7O2 4CO2 + 6H2O + [5] i. How many moles of carbon dioxide are produced on complete combustion of one mole of ethane? ii. What volume at STP is occupied by the number of moles determined in (i) above? iii. What mass of carbon dioxide is produced on burning of two moles of ethane ? [C=12 ; O=16] iv. What is the empirical formula of ethane ? v. What volume of oxygen at STP is required to burn two moles of ethane? g. i. Define. [2] B Avogadro s Law (A) Pyrolysis ii. Give a chemical term for the following. [3] (A) The ratio of the mass of a certain volume of a gas to the mass of an equal volume of hydrogen under the same conditions of temperature and pressure. O || (B) Organic compounds containing a C functional group. (C) Substances which absorb moisture from the atmosphere without dissolving in it. Section II (40 marks) Attempt any four questions from this section. Question 2. a. With reference to the first three periods of the modern periodic table, answer the questions: [5] i. Write the formula of the chloride of the element with atomic number 14. ii. State the term given to the amount of energy required to remove a loosely bound electron from the outermost shell of an isolated gaseous atom. iii. Name the family of elements to which Beryllium belongs. iv. State the type and nature of the bond present in the hydride of the element with atomic number 7. v. Represent the above compound (iv) using an electron dot structure. b. Give the IUPAC names of the following compounds. i. C CH=C CH2 CH3 ii. | CH3 iii. CH3 CH2 CH2 CH2 CH2 OH [3] CH3 | CH3 C Br | CH3 c. Identify the type of isomerism in the following examples. i. CH3 CH=CH CH3 ii. CH3 CH2 CH2 CH2 CH3 , , CH2=CH CH2 CH3 CH3 | CH3 CH CH2 CH3 Question 3. a. Name the product at the cathode and anode during the electrolysis of : i. Molten sodium chloride with inert electrodes. ii. Molten lead bromide with inert electrodes. iii. Acidulated water with inert electrodes. iv. Acidified copper sulphate solution with inert electrodes. b. Explain : During electroplating, a direct current is used. c. 0.29 gms of a hydrocarbon when burnt completely in oxygen produces 448 ml of carbon dioxide at STP. Calculate : i. The mass of carbon dioxide formed. ii. The mass of element carbon in carbon dioxide. iii. The mass of hydrogen in hydrocarbon. iv. The empirical formula of hydrocarbon. Question 4. a. Write balanced chemical equations with conditions for the following conversions. i. Ethnol Diethyl ether ii. Ethanol Ethanoic Acid iii. Ethanol Sodium ethoxode iv. Ethyne Oxalic Acid v. Ethanoic Acid Ethanol (with reducing agent) i. ii. iii. iv. v. [2] [4] [1] [5] [5] b. Answer the following questions. [5] What special arrangement is used for the preparation of hydrocholric acid from hydrogen chloride gas and state its purpose Why nitric acid cannot be concentrated beyond 68% by boiling ? Name the type of salt formed at temperature above 200 C in the laboratory preparation of hydrogen chloride gas and what is its disadvantage. Why is excess of slaked lime used in the laboratory prepration of ammonia? Name the catalyst used in the manufacture of nitric acid and why is it only initially heated ? Question 5. a. With reference to metallurgy, answer the following questions. i. Give the chemical formula and the common name of the halide of aluminium ore. ii. Name the constituents and uses of the following alloys : (A) Duralumin (B) Type Metal iii. Name the process by which (A) The sulphide ores are concentrated. (B) The impure zinc spelter is purified. iv. Electrolytic reduction of pure alumina is difficult. Explain. [5] b. Answer the following questions with reference to the flowchart given below. [5] i. Give an equation to show the roasting of zinc blend. ii. State the compound required to convert solid product X to metal M . iii. Name the catalyst used to convert gas ) to gas )) . iv. Give equations to show how gas )) is converted to sulphuric acid. Question 6. a. Fill in the blanks from the choices given below. [3] 2+ i. M is a metal which forms M ions and thereby undergoes ____________(oxidation / reduction). ii. Its oxide MO will be ______________(acidic / basic). iii. Electronegativity is an ability of an atom to attract ____________(share pair / lone pair) of electrons towards itself. b. What would you observe when : i. Blue litmus solution is added to a solution of ferric chloride. ii. Red litmus solution is added to a solution of sodium sulphate. [2] c. What is the structural formula of the following compounds : i. 2-chloro-3-metyl-but-2-ene ii. Propanal d. i. Write the balanced chemical equation for the laboratory preparation of ammonia gas with a nitride of trivalent metal. ii. Name the method of collection of ammonia gas. iii. State the method of identification of ammonia gas formed. Question 7. a. Select from the following list a substance to match the description given in (i) (v) (Note : The substances listed are to be used only once.) ( Sodium Hydroxide, Helium, Hydrogen Chloride, Tungsten, Ethylene, Carbon Tetrachloride, Graphite, Acetylene, Ammonium Hydroxide and Iodine ) i. Conducts electricity in solid state. ii. Consists of ions only. iii. Contains a triple bond. iv. Does not conduct electricity being a liquid. v. Is monoatomic. b. Give Reasons. i. Nitric acid is a stronger oxidising agent in the concentrated state of the acid than in the dilute state. ii. Electrolysis is considered to be a redox reaction. iii. Almost 90% of all known compounds are organic in nature. iv. Isomers belonging to the same homologous series may differ in physical properties but not in chemical properties. v. Ionic compounds are generally soluble in water but insoluble in organic solvents. [3] [5] [5]
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