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ST. STD :X HIGH SCHOOL GREGORIOS PRELIMINARY EXAMINATION CHEMISTRY DATE:10.01.2024 The frst 15 minutes are for reading No. of Pages: 10, MARKS:80 only. No writing work is to be TIME: 2hours excluding this reading t me.done during this time. The writing time Section Aiscompulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets [] SECTION A (Attempt allquestions from this Section) Question 1: Choose the correct alternative: () The vapour density of a (a) 128 (b) 64 (c) 16 (a) 32 compound is 32, the RMM of the [13] compound is: (ii) The compound used along with soda lime, to prepare ethane is: (a) sodium ethanoate (b) sodium acetate (c) sodium propanoate (d) sodium hydroxide (ii) Hydrogen chloride gas is collected by: (a) Upward displacement of air (b) Downward displacement of air. (c) Upward delivery. (d) Downward displacement of water. (iv) When the pH paper tested could be: turns (a) sodium hydroxide orange in colour, it indicates that the solution being (b) Pepsi (c) human blood (d)sea water (V) A, B,Cand Dare four solutions which are treated with NaOH and treating the four solutions NHOH. On with excess of the reagents, the were made with respect to the following observations precipitates A C D formed. NaOH Soluble Insoluble NH,OH Soluble Insoluble Insoluble Soluble Soluble Insoluble The cations present in each of the solutions are: (a) Zn, Mg*, Pb*2, Cu2 (b)Ca*, Mg, Pb, Cut2 (c) Zn,Ca, Pb*2, Cut2 (d) Zn, Mg*,Pb, Ca2 (vi) Elements X and Y belong to the same period of the affinity of an element X is greater than that of statements is true? (a) Xis placed to the right of Y. (b) X isplaced to the left of Y. (c) The atomic size of X is greater than Y. (d) X is more metallic thanY. periodic table. The element Y. Which of the electron following (vii) Agas cylinder holds 5g of hydrogen and 35g of gas X. Considering the same conditions of temperature and pressure, the vapour density of gas Xis: (a) 5 (b) 35 (c)7 (d) 14 (vii) is an alkaline earth metal and is an alkali metal. (a) Calcium, magnesium (b) Calcium, sodium (c) Sodium, magnesium (d) Potassium, magnesium 2 While (ix) (a) electroplating an article with silver, the correct combination is: cathode: silver block, anode: article, electrolyte: silver b)cathode: article, anode: silver block, electrolyte:silver nitrate cathode: silver block, anode: article, electrolyte: sodiumnnitrate silver () cathode: article, anode: silver block, electrolyte: sodium silver cyanide cyanide ( The IUPACname of the compound with trivial name dimethyl acetylene is: (a)1-Butyne (b) 2-Butyne (c) 1-Butene (d) 2-Butene (xi) Solder is used for making: (a) utensils. (b) aircrafts. (c) bells () electrical fuses (xii) The ore which does not have to be converted to its oxide is: (a) Zinc blende (b) Bauxite (c) Iron pyrites (d) Calamine (xii) The reagent which yields abrown precipitate when excess ammonia gas is passed through it, is: (a) Alkaline pyrogallol (b) Nesseler's reagent (c) Ferrous sulphate (d) Ferric chloride xiv) The catalyst used during Haber's process is: (a) Vanadium pentoxide (b) Finely divided iron (c) Molybdenum (d) Platinised asbestos (xv) The oxidised product formed when concentrated sulphuric acid reacts with copper is: (a) Copper sulphate Question 2: () Complete the following by choosing the correct answers from the braCket: (a) Dressing of the bauxite ore is done by [Baeyer's/ Hall Heroult's] process. (b) For the electrolysis of molten lead bromide, preterred as the anode. (c) [iron graphite] is [CsHi C_Hs] is the molecular formula of an alkyne. (d) Chlorine gas is evolved when |manganese dioxide/ copper oxide] is treated with concentrated hydrochloric acid. (e) ( ) (ethanol ethyne] is used for artificial ripening of fruits. The set up shown is of the electrolysis of copper sulphate. Study the same and answer the questions: (a) In what state is the electrolyte? (b) What is the nature of the electrodes? (c) (d) State your observations. Copper cathode Give the electrolytic reactions taking place: (i) At the cathode (ii) At the anode (e) Copper anode Copper satphae What changes would you observe if platinum electrodes were used for the process? (iii) Match the columns: Column A Column B (a) Nitric acid t carbon (1) Reducing action (b) (c) (d) (e) (2) Non-volatile acid (3) Dibasic acid (4) Dehydrating nature Sulphuric acid + glucose Hydrochloric acid + iron sulphide Sulphuric acid + sodium chloride Ammonia + lead oxide (5) Oxidising nature (6) Acidic nature 4 iv) Identify the following: (a) The compounds of metals along with their earthly impurities. () The oxidising electrode. (c) The formula of a compound which shows the simplest whole number ratio between atoms of the elements in the compound. (d) The compounds in which the shared pair of electrons are unequally distributed between the two atoms. (e) The property by which organic compounds have same molecular formula but different molecular arrangement. (v) (a) Draw the structural formula of the following: (1) Neopentane. (2) (3) 3-pentanol. Propionic acid. (b) Name the following organic compounds in IUPAC system: (1) H H-C-C=C-C- H H (2) H-C-C-C- H H SECTION B (Attempt any four questions) Question 3 )/ Identify the anion present in each of the following compounds: (a) On adding silver nitrate solution to Compound A, awhite precipitate is obtained which is soluble in ammonium hydroxide. (b) On adding dilute nitric acid to Compound B, agas is obtained which tums lime water milky. [21 (ii) Justify the following statements: (a) Oxygen molecule has a double covalent bond and nitrogen triple covalent bond. (b) Zinc hydroxide is amphoteric in nature. molecule has a (1 ) In the metal activity series, Xis a metal above hydrogen. X,O, is the oxide ot metal X. (a) What kind of bond is formed between X and 0? (b) How many valence electrons does X have? Which group does A belon to? (c) Give the formula of the sulphate and the nitride of X. (iv) Answer the following questions based on the manufacture of nitric acid: (a) Give a balanced equation for the reaction taking place in the catalytie chamber. (b) (c) The gases leaving the catalytic chamber are passed through cooling coils. Why? Name the substance used in the absorption tower. Why is it packed in layers? Question 4 (i) Match the columns: Column B ColumnA (1) |Cu+Zn (a) Duralumin (2)Al+Mg+Mn+Cu (b)Brass (3) CutZn+Sn (4) Pb+Sn (c) Solder (d) Bronze (ii) Solutions A, B, C, D are given such that A-is a strong acid B- is a weak acid C- is astrong alkali D-is a neutral solution Which of the solutions: 6 could be glacial acetic acid? (a) (b) would have high concentration of ions? (i) (c) would give a precipitate with lead nitrate solution? (d) would contain only molecules? Ahydrocarbon contains 85.7% of carbon. The vapour density of the hydrocarbon is 21. Calculate the empirical formula and the molecular formula of the [3] hydrocarbon. [C = 12, H= 1] (iv) What do you observe in each of the following cases? (a) [3] Catalytic oxidation of ammonia. (b) Concentrated nitric acid is added to copper. (c) Ammonium hydroxide is added to zinc sulphate first in limitedquantity and then in excess. Question 5 (i) (ii) Answer the following questions based on the manufacture of sulphuric acid: (a) Name the process. (b) Give the balanced equation for the reaction requiring a catalyst. (c) Name the product obtained in the absorption tank. Give reasons for the following questions based on the extraction of aluminium: a) (b) [2] [21 Why is cryolite added to the electrolytic mixture? Why is powdered coke sprinkled over the electrolytic mixture? (ii) Draw the electron dot structure of the following: (a) Ammonium ion (b)Calcium oxide (c) Methane [3] (iv) Give balanced equations for the (a) (b) (c) Question 6 (i) (ii) following: Preparation of methane using an alkyl halide. Preparation of ethyne using calcium carbide. Catalytic hydrogenation of ethene. Ditferentiate between methane and sodium chloride based on: (a) Forces of attraction. (b) Solubility. Mahesh has been given the following substances: Iron, copper, zinc, sodium sulphate, sodium carbonate, hydrochloric acid, sulphuric acid, nitric acid, lead chloride, lead oxide, lead nitrate he has to prepare two compounds. What is the right combination of substances required for each preparation? (a) Lead sulphate. (b) Zinc sulphate. (ii) State the conditions required for the following reactions: (a) Dehydration of ethanol. (b) Esterification (c) Reaction of ethane with chlorine. (iv) Study the extract of the periodic table given below and answer the questions using only letters. 1 |23 A 4567 89 10 11| 12| 13| 14 15 16| 17 18 CID K|L F MN ST Which element: 8 G HI B J PQR (a) has the highest electronegativity? (b) is non-metallic, has valency -2 and lies in period 2? (c) forms an amphoteric oxide? (d) has electronic (e) configuration 2,8,7? has the highest ionization potential? (f) is the most metallic among group 1 elements? Question 7 () ( ) Sarita has been given lead nitrate and silver nitrate solutions. She uses dilute hydrochloric acid to identify the twosolutions. Note down the which will help her to identify them. observations [2] Match the following: (2] Column A(Series) (a) Alcohol (b) Aldehyde (c) Carboxylic Acid (d)Alkane Column B (General Formula) (1) CH0 (2) CH:OH (3) CHn+2 (4) C,HanO CutupH. (ii) Answer the following questions: (a) State Gay Lussac's law. (b) Give the balanced equation for the combustion of ethane. [3] (c) When 1800cc of oxygen is burnt with 1500cc of ethane, what is the volume of unused oxygen? <iv) Explain the following: (a) Ammonia gas is collected by downward displacement of air. (0) Anall-glass apparatus is used in the laboratory preparation of nitric acid. (9) Dilution of concentrated sulphuric acid is done only by addition of acid to water. (3] Question 8 (i) Define: (a) Electron affinity (3) (b) Avogadro's law (c) Catenation (i) Diferentiate between the following: [2] (a) Ferric chloride and ferrous sulphate (using sodium hydroxide) (b) Zinc nitrate and Calcium nitrate (using ammonium hydroxide) (ii) Answer the following questions based on the (a) Give the balanced equation for the (b) laboratory preparation of ammonia: [21 preparation. Name areactant and a drying agent which cannot be used for the (iv) 10g of calcium carbonate is treated with dilute hydrochloric acid. (a) Complete the equation:CaCO; +2HCI CaCl + (b) Calculate: The weight of calcium chloride formed. (c) Calculate: The volume of the gaseous product at S.T.P. L=12, (a H0, 0>\6.0:35-S process. (3)
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