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GOKULDHAM HIGH SCHOOL &JUNIOR COLLEGE SECONDARY SECTION (2023-2024) PRELIMINARY EXAMINATION SUBJECT: CHEMISTRY (SCIENCE PAPER ID MARKS: 80 TIME: 2 hours GRADE: 10 DATE:04.01.2024 Answers to this Paper must be written on the paper provided separately. > You willnot be allowed to writeduring 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 Ais compulsory. Attempt any four questions from Section B. > The intended marks for questions or parts of questions are given in brackets > This paper consists of 10 printed pages. SECTION A Question 1 (Attempt all questions from this section) Choose thecorrect answers to the questions from the given options. [15] (Do not copy the question, write the correct answers only.) i) Which of the following properties do not match with elements of the halogen fanmily? a. They have seven electrons in their valence shell. b. They are highly reactive chemically. C. They are metallicin nature. ii) d. They are diatomic in their molecular form. A molecule containing a triple co-valent bond is: a. Ammonia b. Ethane iii) c. Ethylene d. Acetylene Among the period 2 elements the one which has high electron affinity is: a. Lithium b. Chlorine C. Fluorine d. Neon 1 GRADE 10 iv) CHEMISTRY(SCIENCE PAPER II) Carbon dioxide and sulphur dioxide gas can be distinguished by using: a. Moist blue litmus paper b. acidified potassium dichromate solution C. Lime water V) d. Moist red litmus paper Ine metal oxide which can react with acid as well as alkali is: a. Silver oxide b. Aluminium oxide C. Copper [II] oxide d. Calcium oxide vi) n the circuit given below, the lamp lights up. be? What could the electrolyte DC suppy Lamp Anode -Cathode Electrolyte a. Alcohol b. Solid potassium chloride C. Solution of sodium chloride in water d. Sugar solution vii) The drying agent used to dry NH3 a. POs gas is : b. conc.H,SO4 c. CaClh d. CaO vi i) The pH of a solution which reacts with ammonium chloride to liberate a gas which turns to phenolphthalein colourless pink is: a. Less than 7 b. 7 C. Less than 3 d. More than 7 2 CHEMISTRY (SCIENCE PAPER II) GRADE 10 ix) Which of the following takes place during the electrolysis of aqueous copper [|I|sulphate using copper electrodes? P: Copper ions are formed at cathode Q: Reduction reaction takes place at cathode R: Copper anode shows a loss in mass S: Aqueous copper sulphate solution loses its blue colour a. P and ) b. Q only C. Q and R d. P and R x) A A*, B B, Number of electrons present in the outermost shell of atoms A and B respectively are: a. 2,3 b. 3,2 C. 2,5 d. 6,5 xi) When fused lead bromide is electrolysed ,we observe: a. A silvery grey deposit at anode and a reddish brown deposit at cathode b. A silvery grey deposit at cathode and a reddish brown fumes at anode. C. A silvery grey deposit at cathode and a reddish brown deposit at anode. d. Silvery grey fumes at anode and reddish brown fumes at cathode. xii) The hydrocarbon which can form substitution compounds only is: a. CH, b. CzH, c. CH; d. CH, xiii) Which of the following metal oxides cannot be reduced by nomal reducing agents? a. Zinc oxide b. Magnesium oxide C. Copper [I]oxide d. Iron [1I]oxide 3 CHEMISTRY (SCIENCE PAPERI) GRADE 10 Xiv) The table shows electronic configuration of four elements. Element Electronic configuration W 2.6 X Y 2,8 2,8,1 2,8,7 Which pair of atoms will form a covalent compound? a. two atoms of X b. an atom of W and an atom of X. C. two atoms of W d. an atom of Y and an atom of X. xv) The organic compound mixed with undistilled alcohol to make it spurious is: a. Pyridine b. Methanal C. CuSO4 d. Methanol Question 2 i) Dry ammonia is passed over black substance 'A' as shown in the figure below: [5] dry smmonka gae fungco Ice cubes wzter a. Name the black substance 'A' b. Name the gas evolved 'B' c. Write a balanced equation for the reaction of ammonia with A. d. What doyou observe when ammonia gas is passed over Lead oxide? e. State the property of ammonia illustrated in the above equation. 4 GRADE 10 CHEMISTRY(SCIENCE PAPER II) ii) Match the following Column A with column B (5] Column A Column B a) Alkynes 1.Sulphide ores 2. No. of molecules in 22.4 dm' of ammonia at s.t.p b) Alkanes d) Calcination 3. C,H2n +2 4. ChH2n 2 e)6.023 x 1023 5. Carbonate ores c) Roasting ii) State one relevant observation for each of the following: (5] a) When crystals of copper nitrate are heated in a test tube. b) When the gaseous products obtained by dehydration of ethyl alcohol is passed through bromine water. c) When hydrogen sulphide gas is passed through moist lead acetate paper. d) When ammoniagas is burnt in an atmosphere of excess of oxygen. e) Silver nitrate solution is added to dilute hydrochloric acid. iv)a) Calculate the weight of quicklime formed when 82 grams of calcium nitrate is heated. Also find the volume of nitrogen dioxide evolved at the same time. [2] [Ca=40,Q-16, N=14] 2CaO + 4NO, + O2 2Ca(NO;)2 b) Write balanced equation for each of the following. [3] 1.Ammonia gas reacting with excess chlorine. 2. Action of sodium hydroxide with iron [II]| chloride solution. 3.Preparation of ethyl alcohol from ethylchloride. v) a) Write the IUPACnames of following compounds: 1. H,C -CH (-0 CH, OH 2. CH-CH-CH-CH; CI Br 5 [5] CHEMISTRY (SCIENCE PAPER II) GRADE 10 b) Draw the structural formula for the following compounds: 1. Branched isomer of butane 2. First member of alcohol 3. Acetic acid Question 3 SECTION -B (40Marks) (Attempt any four questions from this section) i) Identify the anion present in each of the following compounds. (2] a) When barium chloride solution is added to a solution of compound B, awhite precipitate insoluble in dilute hydrochloric acid is formed. b) When dilute sulphuric acid is added to compound D, a gas is produced which turns lime water milky but has no effect on acidified potassium dichromate solution. ) Write equations for the reaction taking place at the cathode and anode during the electrolysis of : (2] a) Acidified copper sulphate using copper electrodes b) Acidified water iiil) Fillin the banks: [2] 1. Ionisation energy (increases/decreases) on moving across the period. 2. Electronegativity down the group. (increases/decreases)on moving iv) Draw the electron dot structure for the following: a) NH, b) CCl4 6 (4] CHEMISTRY (SCIENCE PAPER II) GRADE 10 Question 4 i)The vapour density of a gas is 8. What would be the volume occupied by 24 gm [2] of the gas at STP? ii) Distinguish between the twocompounds for the following: [2] a) Copper oxide and Manganese dioxide. b) Dilute hydrochloric acid and dilute sulphuricacid. iii) Non metals combine by sharing electrons to form compound X. a) What type of bonding will be present in X? [3] b) WillX have high or low melting point. Why? c) Will it be a good conductor of electricity or not? Justify. iv) Write balanced equations for each of the following: [3] a) Oxidation of sulphur by conc.Nitric acid. b) Sodium carbonate with dil.Hydrochloric acid. trioxide. c) Conversion of sulphur dioxide to sulphur Question 5 i) An metal X has valency 3 and a non- metal Y" has 7 electrons in its M shelI. a) Is "y" a reducing or oxidising agent? [2] b)Write the formula when Y combines with X. [2] ii) Name/state the following: a) Analloy of copper that is used to make statues. b)The products formed when an acid reacts with a base. preparation of ii) Answer the following questions with reference to the laboratory [3) Hydrogen chloride gas: a) Write balanced equation for the reaction. b) Name the method used for the collection of gas and why? c) Give reason : Conc.H,SO, is preferred as a reactant in the preparationof Hydrogen chloride gas. 7 CHEMISTRY (SCIENCE PAPER I) GRADE 10 iv)Calculate the relative molecular mass [molecular weight] of 290 ml. of agas A' at 17 Cand 1520 mm pressure which weighs 2.73g at s.t.p. [Ilitre of hydrogen at s.t.p. weighs 0.09 g.] [3) i)Give balanced chemical equations for the following conversions: [2] Q estion 6 a) Calcium carbide to ethyne Bb) Ethanoic acid to ethylethanoate |4) ii) Identify the term: a) The property of elements by virtue of which atoms of the element can link toeach other in the form of a long chain structure. b) Anhydrous acetic acid when cooled below 16.5 C. c) The deposition of superior metal on the surface of base metal by electrolytic process. d) Theorganic compounds having the same molecular formula but different structural formula. iii) Copy and complete the following table which refers to the industrial method for the preparation of Ammonia and Nitric acid: Name of the Name of the process compound (4] Catalytic equations (with conditions if any) Ammonia a b) Nitric acid c d) 8 GRADE 10 CHEMISTRY (SCIENCE PAPER I) Question 7 If 2000cc of i) Ethane burns in oxygen to form carbon dioxide and water vapour. carbon oxygen required and the volume of of volume the find burnt, cunane isS [2] dioxide produced. molecules. how 11)a. If 150ccof gas A contains X many molecules of gas B Wil! conditions B are under the same and A gases The B? of De present in 75cc of temperature and pressure. problem is based. b. Name the law on which the above [2] ore. 3| extraction of aluminium from its the to refer questions 11)The following the concentration of the ore. a) Name the method used for reduction and b)Write the reaction at cathode anode during the electrolytic of alumina. the the electrolyticmixture during over sprinkled coke powdered c) Why is above said process? generally used for preparing following is C or B A, methods the of iv)Which [3| respectively: compounds listed below from l to 3 C.Titration A. Neutralisation B. Precipitation 1) Copper sulphate 2) Ammonium sulphate 3) Zinccarbonate CHEMISTRY (SCIENCE PAPER I) GRADE 10 Question 8 i) Give reasons for each of the following: [2] a) An alkali is used for concentration of bauxite ore during metallurgy of aluminium. b) Funnel arrangement is nceded for the preparation of Hydrochloric acid. ii) Name the property of sulphuric acid and write balanced equation for the following: (2] a) Ci2H2O| ConcH,so4 b) KNO3 +Conc. H,SO4 < 200 C iii) Solution A is a sodium hydroxide solution. Solution B is a weak acid. Solution C is dilute sulphuric acid. Which solution will: a) liberate sulphur dioxide from sodium sulphite. (3] b) give a white precipitate with zinc sulphate solution. c) contain molecules and ions. )Ametal Mforms a volatile chloride containing 65.5% chlorine. If the density of chloride relative to hydrogen is 162.5,find the molecular formula of the chloride (M= 56, CI= 35.5). [3| 10
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