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MOCK EXAMINATION, MARCH 2021 SUBJECT: CHEMISTRY GRADE: 10 MAX. MARKS: 80 DATE: 16/03/2021 TIME: 2 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 allotted for writing the answers. The question paper consists of 6 printed sides. 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) Fill in the blanks with the correct choices given in brackets. [1x5=5] i) The product formed at cathode during electrolysis of aqueous sodium chloride solution___________.(Oxygen gas/ Hydrogen gas/ Sodium metal/ Chlorine gas) ii) Ammonia reacts with excess chlorine to form _________________________. (nitrogen / nitrogen trichloride / ammonium chloride) iii) A covalent molecule containing three single covalent bonds is ______________. (nitrogen / ammonia / water / methane) iv) The alkaline behavior of liquor ammonia is due to presence of ____________ ions. (ammonium / hydronium / hydroxyl) v) An aqueous solution of sodium chloride will contain _____________(ions only/ ions and molecules/molecules only) Page 1 of 6 b) Choose the correct answer from the options given below: [1x5=5] i) The element having highest electron affinity from the following is: A) Bromine B) Chlorine C) Fluorine D)Iodine ii) Ammonium hydroxide will produce a reddish brown precipitate when added to a solution of: A) CuSO4 B) Zn (NO3)2 C) FeSO4 D) FeCl3 iii) The general formula of alkynes is A) CnH2n-2 B) CnH2n+2 C) CnH2n D) CnH2n+2O iv) The substance used to dry ammonia: A)P2O5 B)conc.H2SO4 C)CaCl2 D)CaO v) During the electrolysis of acidified water which of the following does takes place: A) Oxygen is released at cathode B) Oxygen is released at anode C) Hydrogen is released at anode. D) Sulphur trioxide is released at anode c) Write balanced chemical equation for the following conversions along with conditions if any. [1x5=5] i) Ethane to carbon dioxide ii) Ethyne to ethane iii) Calcium carbonate to calcium chloride iv) Sulphur to sulphuric acid v) Ammonia to nitrogen d) Match the following: S.No i) ii) iii) Column I Acetic acid Sulphuric acid Methane [1x5=5] S.No A) B) C) Column II Dimethyl propane Marsh gas Acetaldehyde Page 2 of 6 iv) neo-pentane v) Ethanal e) Ethanoic acid Oil of vitriol Draw the structural formula for each of the following: 1. 2. 3. 4. 5. f) D) E) [1x5=5] Butan -2-ol Pentanoic acid 3- methyl pent-2-ene 2- butyne Propanal State one observation for each of the following: [1x5=5] i) A pinch of copper carbonate is heated in a dry test tube. ii) Silver nitrate is added to sodium chloride solution followed by ammonium hydroxide. iii) Action of concentrated sulphuric acid on sugar. iv) Lead nitrate is heated in dry test tube. v) Sodium hydroxide is added to copper sulphate solution. g) State the term: [1x5=5] i) Uniform deposition of a superior metal over a baser metal using electricity. ii) The tendency of an element to attract electrons towards itself in a compound. iii) The bond formed between metal and non-metal. iv) Type of covalency in which one of the combining atoms contributes both the shared electrons. v) Energy released on adding an electron to the outermost shell of atom in its isolated gaseous state. h) i) A compound has following percentage composition by mass: [2+2+1 =5] Carbon 85.71% and Hydrogen 14.29%.Determine the empirical formula of this compound. (Atomic mass : C=12 and H=1) ii) If the vapour density of the compound is 35,what is its molecular formula? iii) Is it a saturated or unsaturated hydrocarbon? Page 3 of 6 SECTION II -[ 40 marks] [Attempt any four questions from this Section] Question 2 a) Answer the following: [4] i)Ethene undergoes addition reactions. Give reason. ii)Name the next alkene after ethene in the homologous series. iii) Write down the reaction for bromination of ethene and give IUPAC name of the product formed. b) Draw electron dot diagram of: i) H3O+ ii) CaO [3] iii) NH3 c) Answer the following question based on Modern periodic table: [3] i) The alkali metals have _______ (high/low) ionization potential. ii) Define ionization potential. iii) Which element among the following elements from period 3 will have highest electronegativity. Magnesium,Chlorine,Sodium,Phosphorus Question 3 a) Select the anion (from given list) present in each of the following compounds. 1. CO322.NO33.SO424. Cl5.SO32- [5] i) Compound A reacts with conc.H2SO4 producing a gas which fumes in moist air and gives dense white fumes with ammonia. ii) Compound B reacts with dil.H2SO4 producing a gas that turns lime water milky but has no effect on acidified potassium dichromate solution. iii) When barium chloride is added to Compound C, a white precipitate insoluble in dil HCl. iv) Compound D reacts with conc.H2SO4 on heating evolving a coloured gas which turns Potassium iodide paper brown. v) Compound E reacts with dilH2SO4 producing a gas that turns lime water milky and acidified potassium dichromate solution orange to clear green. b) Name the following: [5] i) A greenish yellow gas with pungent smell. ii) A metal oxide which is yellow when hot and white when cold. iii) The property of carbon to form chain or ring structure. iv) The product formed at the anode during electrolysis of molten lead bromide. v) The simplest whole number ratio between the atoms of various elements Page 4 of 6 present in one molecule of a compound. Question 4 a) Answer the following questions when a spoon is to be coated with silver metal. i) Write the dissociation reaction of the electrolyte used. ii) A low current is passed for a longer period of time. Justify. iii) Write observation and reaction at anode. iv) Write observation and reaction at cathode. [6] b) Explain the following. i) Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals. ii) Concentrated nitric add appears yellow when it is left standing in a glass bottle. iii) All glass apparatus is used in the laboratory preparation of nitric acid. iv) Concentrated nitric acid renders Iron and Alumminium passive. [4] Question 5 a) Distinguish between following pair of compounds using a reagent as a chemical test: [6] i) Potassium chloride and potassium sulphate ii) Dilute sulphuric acid and dilute nitric acid iii) Copper chloride and zinc chloride b) In the extraction of aluminium by Hall -Heroult s process: [4] i) Name and state the formula of the ore used. ii) Name the components added to the above ore for the electrolytic process. iii) Why is the electrolyte covered with coke? iv) Name the gas evolved at anode. Question 6 a) The following statement is correct only under certain conditions.Rewrite the correct statement using approperiate conditions. [5] i) Sulphuric acid has a strong affinity for water. ii) Magnesium reacts with Nitric acid to liberate hydrogen. iii) Ammonia is collected by upward displacement of air as the gas is lighter than air and insoluble in water. iv) Sodium chloride will conduct electricity in the solid state. v) Atomic size increases as we move across the periodic table, since the number Page 5 of 6 of electrons increases. b) Write balanced equation to show following properties of concentrated sulphuric acid. [3] i) Oxidation of sulphur ii) Dehydrating agent with hydrated copper sulphate crystals iii) Non-volatile nature in the preparation of nitric acid. c) Write the I.U.P.A.C. names of the following compounds: i) ii) [2] Question 7 a) Given below are the portions of Modern Periodic table and answer the questions that follow. Give the letter corresponding to the element in question. Do not repeat an element. [4] i) Which element forms an electrovalent compound with G? ii) The ion of which element will migrate towards the cathode during electrolysis? iii) Which non-metallic element has the valency of 2? iv) Which is an inert gas? b) The pH values of three solutions A, B and C are 12,2 and 7 respectively. Answer the following questions. [2] i) Which solution will liberate carbon dioxide when reacted with sodium carbonate? ii) Which solution will turn red litmus solution blue? c) Copy and complete the table relating to important industrial process. Output of the process refers to the final product of the process not the intermediate step. Page 6 of 6 [4] Name of the process Input Catalyst Equation for the catalysed reaction Output Nitric acid ********************************************************************************************************** Page 7 of 6
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