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GARDEN HIGH SCHOOL CLASS X Prelims, 2023 24 Chemistry Time: 2 hours Full Marks: 80 This Question Paper has seven printed pages. Answers must be written in the script/s provided. You will not be allowed to write for the first 15 minutes. This time must be spent in reading the Question Paper. The time given at the head of this Paper is the time allowed for writing answers. This Paper is divided into two Sections. Answer all the questions of Section A and any four of Section B. All parts of a question must be answered together in the correct order. Maximum marks for a question or parts of a question are given in brackets [ ]. SECTION A (40 marks) Answer all the questions. Question No 1 Choose the correct options: [15 1 = 15] (a) The weak electrolyte is (i) dilute hydrochloric acid. (ii) dilute sulphuric acid. (iii) sodium chloride solution. (iv) aqueous acetic acid. (b) The salt that is soluble in excess of both sodium hydroxide and ammonium hydroxide is (i) calcium nitrate. (iii) zinc chloride. (ii) ferric chloride. (iv) lead chloride. (c) Given: A A3+; B B 1 The number of electrons present in the outermost shell of atoms A and B respectively are (i) 5, 1. (ii) 3, 1. (iii) 3, 7. (iv) 5, 7. (d) The organic reaction that does not come under addition reaction is (i) hydrogenation. (iii) halogenation. (ii) dehydration. (iv) hydrohalogenation. (e) The alkene which decolourizes bromine water is (i) C6H14. (ii) C2H6. (iii) C3H4. (iv) C2H4. (2) (f) The empirical formula of a compound is EF4. If its empirical formula weight is equal to its vapour density then its molecular formula would be (i) E4F. (ii) E2F8. (iii) EF2. (iv) EF4. (g) Copper and aluminium are the main components of the alloy (i) brass. (iii) steel. (ii) solder. (iv) duralumin. (h) An inert electrode used in the electrolysis of acidified water is (i) graphite. (iii) iron. (ii) platinum. (i) (iv) copper. On heating 12.3g of MSO4. xH2O 6 0g of anhydrous salt is left behind. If atomic weight of M is 24 then the value of x is (i) (j) 5. (ii) 4. (iii) 3. (iv) 7. The main ore used for the extraction of iron is (i) haematite. (ii) calamine. (iii) bauxite. (iv) cryolite. (k) Which of the following statements is correct about an aqueous solution of an acid and a base? (A) Higher the pH, stronger the acid (B) Higher the pH, weaker the acid (C) Lower the pH, stronger the base (D) Lower the pH, weaker the base (i) (l) (A) and (C) (iii) (B) and (D) (ii) (B) and (C) (iv) (A) and (D) The correct arrangement of the given elements in the increasing order of metallic character is: (i) Na > Mg > Al > Si > Cl (iii) Cl < Si < Al < Mg < Na (ii) Cl > Si > Al > Mg> Na (iv) Al < Si < Mg < Na < Cl (m) Which of the following weighs the least? (i) 2 gram atoms of nitrogen (ii) 1 mole of silver (iii) 22.4 litres of oxygen gas at 1 atmospheric pressure and 273K (iv) 6.023 1023 atoms of carbon (3) (n) The figure given below shows an experiment carried out between conc sulphuric acid and sodium chloride, which react with each other to form HCl gas. Delivery tube A blue litmus paper is brought near the mouth of the delivery tube to check the presence of HCl acid but no change is observed in the colour of the litmus paper because (i) the litmus paper used is dry. (ii) the litmus paper used is moist. (iii) blue litmus paper does not change colour in the presence of an acid. (iv) the litmus paper is kept very close to the mouth of the delivery tube. (o) The most reactive element in the periodic table is (i) Cs. (ii) Li. (iii) Na. (iv) K. Question No 2 (a) The diagram given below shows an electrolytic method for the manufacture of aluminium from one of its ores. (i) Name the method. (ii) Name the substances denoted by R, T, U, V, W, X and Y. (iii) Write down the reactions that take place at the electrodes. [5] (4) (b) Correct the following statements by adding appropriate word/s. Rewrite the correct statement. [5] Example: Copper sulphate crystals are dehydrated by sulphuric acid. Answer: Copper sulphate crystals are dehydrated by concentrated sulphuric acid. (i) The electrolysis of lead bromide liberates lead and bromine. (ii) Ammonia is oxidized to nitric oxide. (iii) Hydrogen chloride fumes in air. (iv) Hydrochloric acid is prepared by the funnel arrangement method. (v) Barium nitrate reacts with sodium sulphate to form barium sulphate. (the same word is required in two places.) (c) Name/State the following: (i) [5] The energy released when chlorine gas is converted to chloride ion (ii) The self-linking property of carbon atom (iii) A salt formed by the complete neutralization of an acid by a base (iv) A compound that burns in excess of oxygen to form carbon dioxide and water as only product (v) An acid that can form two different salts (d) Arrange the following in increasing order of (i) [5] size: Ar, Kr, He, Ne (ii) lone pair of electrons: water, methane, ammonia, hydrogen chloride (iii) pH: distilled water, caustic soda, acetic acid, liquor ammonia (iv) single covalent bond: ethane, methane, ethyne (v) electrovalency: Cl, Mg, P (e) Match and pair: (i) reactants of Ostwald s process [5] (A) hydrogen chloride (ii) action of concentrated sulphuric acid on rock salt (B) carbon dioxide (iii) action of sulphuric acid on sulphur (C) nitrogen dioxide (iv) gas that forms during calcination of ores (D) sulphur dioxide (v) nitric oxide comes in contact with air (E) ammonia and oxygen (5) SECTION B (40 marks) Answer any four questions. Question No 3 (a) Study the diagram given below and answer the following questions: (i) [5] Identify Q and R. (ii) What is the function of the U-tube dipped in ice and water? (iii) State the property of ammonia demonstrated in the above experiment. (iv) What change do you observe in the glass tube at the end of the experiment? (b) Give one chemical test to distinguish between the following compounds: (i) [5] Dilute nitric acid and concentrated nitric acid (ii) CuO and C (iii) Sodium sulphite and sodium sulphate (iv) Dilute nitric acid and dilute hydrochloric acid (v) Ammonium chloride and sodium chloride Question No 4 (a) If 1200 cc of oxygen is burnt with 300 cc of ethane to give carbon dioxide and water, then calculate: (i) [2] The volume of carbon dioxide formed. (ii) The volume of unused oxygen. (b) Copy and complete the following table: Formula of the compound [4] Reaction with aqueous acidified barium chloride Reaction with few drops of aqueous sodium hydroxide (i) White precipitate Blue precipitate FeCl3 (ii) (iii) (iv) White precipitate No precipitate (6) (c) Give the IUPAC names of the following compounds: (i) [4] (iii) OH (ii) (iv) Question No 5 (a) Write the names of the substances A to E. [5] (b) Write the balanced chemical equations for the following reactions. [3] (i) Hydrochloric acid + black solid B A (ii) E + D + H2O acidic solution (iii) HCl + sodium sulphite E (c) Find the total percentage of oxygen in washing soda. [2] [ Na = 23, C = 12, O = 16 ] Question No 6 A hydrocarbon X contains 85.7% carbon by mass. (a) Determine the empirical formula of X. [3] (b) If the relative molecular mass of X is 28, find the molecular fomula of X. [1] (c) Name X. [1] (d) Write the structural formula of X. [1] (e) What is the special feature of X that determines the type of reaction it undergoes? [1] (f) [2] How would you convert X to C2H6? (g) If X normally undergoes addition reactions, what type of reaction does the compound C2H6 undergo? [1] (7) Question No 7 (a) The diagram given below shows the electrorefining of copper used for purification of the metal. Name the following with reference to the electrorefining of copper. (i) [6] The anode used. (ii) The cathode used. (iii) The ions present in the electrolyte. (iv) The products formed at the electrodes. Explain why the concentration of aqueous copper sulphate, does not change during the electrorefining process. (b) Draw the structures of the following organic compounds: (i) [4] The first homologue whose general formula is CnH2n (ii) The compound formed by the complete chlorination of ethyne (iii) The position isomers of C4H8 (iv) Chain isomers of isobutane Question No 8 Give balanced chemical equations to carry out the following conversions. N2 (ii) (a) Mg3N2 (i) (b) CH3COONa NH3 (vii) (iii) NO CH4 (iv) (viii) NO2 CH3Cl (v) (ix) HNO3 (vi) CH3OH NaNO3 (x) CH3COOCH3 [10]
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